Experienced with the TWM P-51 GS?
 

The fuselage behind the Wingman II is from a P-51D Mustang G.S. ( S4 - Yellow ) A100S4 on the P-51 Mustang G.S. page.

People have run Moki 2.1 engines in these, but I'm going a bit different. I'm going to try a gasser and go with the O.S. GT33 Gasoline engine. The weight should be about right. Might need a little tail weight, but I may put dual elevator servos in the tail. Haven't measured the firewall yet, so I don't know for sure it it will fit. The engine comes with a muffler. If it works out, it might be a lot of fun.

I'm looking for people experienced with the World Models A100S line of G.S. (Giant Scale) P-51 planes. I've seen threads occasionally mention 2 stroke engines in them. But that was a while ago..

So any input is appreciated. Pictures of installations, anything is helpful. Retract advice, etc.

One thing they did change from the old model to the new model is the elevator system. The older model used a pull-pull affair where as the pull one doesn't. If you have done the dual elevator servo thing at the rear, I would be especially interested in seeing pictures of that, and knowing how it works out..

RE: Experienced with the TWM P-51 GS?
 

I actually have two of the Mustangs to work with. The Miss America is the latest production model. It has some changes and looks even better. The wing fillets are nice and are made of fiberglass. The canopy looks different. May just be optical but I think it is shaped better. The new models come in two boxes for easier shipping. They also don't use the pull-pull elevator system.

The Miss America looks sharp. It won't get a custom color scheme.

I'm going to give the yellow one a custom color scheme. One of my usual gaudy things. Or maybe I'll try to do something classy for a change. Maybe copy a Lyle design. It won't be a boring scale design though. It will be more of Q40 type of racing scheme.

In terms of engines, if someone has tried the [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXZZH1&P=M]DLE Engines DLE-30cc Gas Engine Rear Carburetor[/link] or the [link=http://www.cermark.com/products/MLD-35cc-Gasoline-Engine-%252d-MLD%252d35.html]MLD 35cc Gasoline Engine - MLD-35[/link] in one of these planes, I would be especially interested in your experiences.

RE: Experienced with the TWM P-51 GS?
 

It will fly just fine with the OS 33 but if you want more speed you should rung a DLE 55 or even the EVO 58 for around 130MPH

RE: Experienced with the TWM P-51 GS?
 

I took the time to take a few pictures and measure the space this morning. With the cowl as far out as it seems feasible, the distance from the firewall to the spinner ring is 6.5" that opens up a lot of possibilities without having to do significant firewall mods.

Even though tail weight would be required my original thought for powering this plane was the [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXYNR4&P=ML]O.S. GT55 Gasoline[/link] ... I like the front mounted carb form factor and with the tighter firewall, this might be a choice for some "get up and go".

But that [link=http://www.troybuiltmodels.com/items/DL55ENGINE.html]DLE Engines DLE-55 55cc RC Model Gas Engine with Muffler and Electronic Ignition[/link] might be the ticket as well. I've heard it runs well.

This plane is not quite legal for the USRA class at [link=http://usrainfo.org/wbird.htm]USRA Provisional Class: WARBIRD[/link] as the wing are is 45 sq in too small at 1155 and they require 1200. But that is a PROVISIONAL class and in my opinion changes can be made to a provisional class or a new class can be created.

RE: Experienced with the TWM P-51 GS?
 

This afternoon I took the wing and tail out of the plastic and stuck the yellow P-51 together. It's pretty big, but not so big that transportation is any worse than any other large scale plane.

it is pictured with my P-51 EP also from TWM. Min was one of the originals and I converted the brushed motor to an outrunner and put a reno style canopy from a Voodoo on it. They are available from AirBorne or at least they used to be. The [link=http://ecsvr.com/abm/shopexd.asp?id=2440]P-51 Mustang - EP ( Brushless) Yellow (E194BY)[/link] now comes with a brushless outrunner motor.

The big question about the big one is the engine.

The other big question is the color scheme. I don't go for all yellow airplanes. I like orange and blue on yellow and I like red sunburst on yellow. And obviously I like the red with red/white checkerboard, mainly because I can see it easily and it is easy to do. But for a big plane, I have the time to go fancy. I know fancy color schemes on P-51 planes are not very scale, but I'm going for racy looks. The Miss America sure looks racy.

RE: Experienced with the TWM P-51 GS?
 

James Barr of Liberty South Carolina came to visit me today and we spent time bench running the OS 25 brushless motor for www.ClubWingman.com and looking at the Wingman II.

We also spent a significant amount of time looking at the TWM P-51 GS kits. We found that the newer Miss America has the mounts in place for the dual elevator servo as an option to the pull-pull system.

We talked about engines and in the process I pulled out the aluminum spinner that came with the yellow Rockwell kit. James noted that it weighed almost a pound. I put it on the scale and it was 15.1 ounces. So I got the spinner out of the Miss America kit and it is a plastic spinner with an aluminum backplate. It was 9.7 ounces.

After he left I decided to take some pictures and post them. I realized that there was extra stuff inside them. There was an extra collet and extra hub rings in them. So I took out the extra parts and used just the largest of the collets, weighed, and photographed them.

The difference of 5 ounces would be significant in affecting the balance. The question is are plastic spinners up to 9000+ rpm on a gas engine?

I can't upload photos now. Maybe I've reached my limit.

(edited to add photos)

RE: Experienced with the TWM P-51 GS?
 

you can also drill holes in the back plate the rebalance it. can take a bunch of weight out.

I maybe have to get one of these real soon.

RE: Experienced with the TWM P-51 GS?
 

Your not going to get 9,000 RPM out of a gasser. 7,000 to 7,200 is more ralistic. Anything past that is out of the power band for a muffled gasser.

RE: Experienced with the TWM P-51 GS?
 

Thanks for the tip. I'm from the small plane arena and didn't even think about that.

I did find out that only some of the Rockwell kits have the aluminum backplates. And I found out that the factory has a good supply of Rockwells. The Rockwells are the slightly older model. But the only differences are that they don't have the backing mounts for the dual elevator servos and they don't have the wing fillets.

[link=http://www.rcpro.org]RCPRO[/link] is probably going to create a one airframe racing class based on the [link=http://www.airborne-models.com/html/productdetails.asp?ProductID=21]P-51 Mustang G.S.[/link]. Multiple RCPRO Board members are already getting the planes and engines. We are going to limit the engines to 38cc for a number of reasons. There are a whole range of engines that will fit right in and balance reasonably well. They will not overstress the airframe. I will be publishing a list.

If you are on Facebook, please go to [link=http://www.facebook.com/pages/RCPROorg/223516891052909]RCPRO.org[/link] and check out our photo galleries. More to come. And if you have some we'll get them up. May even create a page just for RC Warbird Racing.

What do you think?

RE: Experienced with the TWM P-51 GS?
 

I created a Facebook page at RC Warbird Racing for ALL R/C Warbird racing. Not just RCPRO Warbird Racing. I included the link for [link]http://www.rcpylonracing.com/[/link] and anyone is welcome to send me links to add. If you want to be a Admin so you can upload photo galleries, contact me. Unfortunately you have to be an Admin to do a photo gallery, but you can post photos all day long.

I'm on Facebook at http://www.facebook.com/don.stegall

I will post a link back to this forum so that people who find the Facebook page can find this forum.

RE: Experienced with the TWM P-51 GS?
 

Here are a couple of pictures of the Rockwell and Miss America.

You can view more detailed pictures of the [link=http://www.abmshowcase.com/the_world_models/scale/p51gs/models/rockwell/photos/default.aspx]P-51 Mustang G.S. - Rockwell Kit Pictures[/link] and [link=http://www.abmshowcase.com/the_world_models/scale/p51gs/models/miss_america/photos/default.aspx]Miss America G.S. - Kit Pictures[/link] on a site I'm doing that features models from The World Models and The Wings Maker. It's not finished yet, but these pictures are done and if you have an interest in the P-51 Mustang G.S. you may find them interesting.

RE: Experienced with the TWM P-51 GS?
 

Hi Don,

You can get 9000rpm out of a gasser. During the giant scale racing at Madera we would turn about 8800 on the ground with our Quadra 75 rss with just 9" straight pipe. We estimated it was unloading to about 10 k in the air. With a big single pumping out that fast, vibration was a problem and we were constantly watching for loose bolts, stressed servos, and just about anything you can imagine due to the vibration of the engine.

We had experimented with soft mounts but we found we lost rpm when the engine was mounted that way. So its was a trade off between vibration and all out speed. In racing, speed is god.

Carlos G.

RE: Experienced with the TWM P-51 GS?
 

Carlos, if I'm not mistaken Don is setting this up for a new class of racing that is going to allow up to 35cc stock, gasoline burningengines. He listed a few earlier in this thread, most reed inducted. Not really a fair comparison to the modified, port inducted alcohol burners you guys were running at Madera. 9,000 RPMs with the engines listed just isn't going to happen.

RE: Experienced with the TWM P-51 GS?
 

Hi Don, Speed,

All I can say is read the rules...

The Quadra/Aerrow was indeed a gasoline engine and also had reed induction. The DLE 30 as advertised will turn up to 8500rpm. 9000rpm is doable with a stock engine if the engine is prepared correctly. It just depends upon how far you are willing to take it.

Some will buy several engines and select the best parts from each to build a engine as close to blue printed engine as possible.

FWIW, you cant have too many spare parts especially retracts.

Good Luck and keep us posted Don.

Carlos G.

RE: Experienced with the TWM P-51 GS?
 

Hi Don,

I went to the RCPRO site and looked at the rules. With the break out time as sort of a governor of the racing I guess reliability and consistancy is the name of the game rather than all out speed.

With the wing area minimum of 400sq inches and a maximum weight of 18lbs., it would seem that there would be a potential for quite a mix of aircraft in a given heat? Is wake turbulance a hazard for the smaller planes?

Looking at the pictures of some of the planes it would appear .60 to .90 size planes are the favored choice at this point.

If there was ever a race in my area I would like to see one to watch how it all works.

Best Regards,
Carlos G.

RE: Experienced with the TWM P-51 GS?
 

If I was starting with a basically stock all yellow airframe then there is only one choice for paint jobs!

http://www.p51models.com/wp-content/...N335JAug78.jpg

RE: Experienced with the TWM P-51 GS?
 

I looked at this plane on the Airborne Models site and would like to know what JR/Spektrum servos you would run in a plane this size. It takes 9 servos.  I suspect 2 flap, 2 aileron, throttle, rudder, 1? 2? elevator, 2 retract<div>
</div><div> I haven't been a large plane person but am interested in this plane.</div>

RE: Experienced with the TWM P-51 GS?
 

Carlos,

RCPRO Warbird Racing ([link=http://RCPROWarbirdRacing.com]RCPROWarbirdRacing.com[/link]) has been going on for quite a while. It started out as a wing area to engine displacement size thing based on SWRA racing, but with the breakout times, it evolved and the RCPRO Warbird Committee decided to remove the area to engine size table because it was too much of a hassle, and in bracket racing the goal is having your equipment work reliably, to fly well, and still be fast and consistent.

What we're working on with the P-51 is a single airframe, no airframe modifications class, with engines limited to 38cc. The engines will be gas only with no alcohol/nitro conversions. This will be pure heads up racing unless we determine there is a need to have brackets.

The spec formula has worked very well for Club 40 Racing ([link=http://Club40Racing.com]Club40Racing.com[/link]) and this might be a way to get people with an interest in large planes to try racing. Plus some of us who have been racing the smaller planes have been wanting to try the bigger planes. The goal with the class we are working on is cost containment and being able to run at many fields. Even if the speed is not real high, the fun comes in the preparation, the competition, and the community. A number of people have moved from Club 40 to AMA 424, AMA 426, and NMPRA EF1.

If you want to see some videos of Club 40 racing, you can go to [link=http://www.abmshowcase.com/the_world_models/sport/sky_raider_mach_2/video.aspx]Sky Raider Mach II - Video[/link].

I guess I need to go ahead and publish the preliminary rules. The new RCPRO content web site will be done in a week. We may change the engine size depending on performance testing though.

RE: Experienced with the TWM P-51 GS?
 

Here is a list of engines identified as candidates for the World Models P-51 Mustang G.S.

DLE Engines DLE-30cc Gas Engine Rear Carburetor

MLD 35cc Gasoline Engine - MLD-35

SE-32

O.S. GT33 Gasoline

PTE36R aircraft engine rear exhaust, rear carb

RCG 30cc Gas engine w/ CD-Ignition 3.9HP/2.94kw

RE: Experienced with the TWM P-51 GS?
 

Carlos, after looking at a Q75 yes you are correct it is reed inducted. My mistake there. Yes originally it is set up for gasoline use but all the guys I know that flew the Giant Unilinteds ( Mike and Chris Lavara, Denny Baker, Kevin Norred just to name a few ) all ran alcohol. There were also extensive mods done as well.

Now take the example of the DLE55. This engine was designed for sport aerobatic type airplanes. We would usually prop that with a 23X8 or 24X8. These would turn around 6,800 to maybe 7,200. This is where the engine is set up to develop it's power. If one was to reduce prop load enough to get it into the 9,000 range it would be out of it's power band and the prop would be too small to have any real use on a WM Mustang. With your racing experience you should know the difference between RPM and usable power. I currently race the SAMs warbird format. I have my own scratch built Macchi 202 powered with a Rossi .61 FIRE. Now I can put on a 10X8 and reach 18,000 on the ground. With that prop the airplane is much slower then if I bolt on a 10X10 that only hits 14,000. Point being, loading the engine with the correct prop that matches the power band of the engine and drag of the airframe is much more important then getting max RPM.


So I would like to appologize to Don for getting his build thread off track and say that if we want to continue this maybe it's better done in the gas engine forum.

RE: Experienced with the TWM P-51 GS?
 

Hi Don

Of the engine you have listed , the PTE 36 appears to have an edge over the others, at least according to the specs. Availability of spare parts may favor a different engine though.

Dont forget the ol' Quadra 35 as an option. Maybe a little heavy but they were inexpensive and reliable. A well broken-in engine can run pretty good too. Its use may depend upon how well it fits the chosen airframe.

If you have the ear of World Models you might suggest a second model, of about the same size, not necessarily the same exact scale. Sea Fury, Bearcat, or Zero or Spitfire. They could use the same retracts in all.

Or perhaps mention a Ready to Cover versions of the P51 so racers would have more flexability choose color schemes and to inspect/reinforce the airframe prior to covering.

The Corsair would need dedicated retracts and may not be as appealing to manufacture due to the inverted gull wing.

A little variety may help the class to get going.

Just a few thoughts for your consideration.

Good Luck,

Carlos G

RE: Experienced with the TWM P-51 GS?
 

Carlos,

Thanks for your interest, thinking, and input.

Things like the reed induction versus port induction will have to be specified or we will have issues. The Evo 40GX would possibly have a significant advantage over reed engines if the spec allowed 40cc engines. We are working with 38cc because there are some other engines in the 36 to 38 range that people have already that they may want to try. I have run across a number of engines in the 30 to 36 range, but I haven't bookmarked every one. I should have. I've been looking for viable sources. I do wonder about the PTE36R and some of the others.

The thing that made Club 40 work was a limited choice of airframes and engines. People knew what to buy. No researching and searching for the best or better. In the beginning we allowed the SIG Four Star 40, the SIG Mid Star 40, and the Sky Raider Mach II (SRM2). The Mid Star was a kit and the Four Star was available as a kit or ARF. Then TWM came out with the LA Racer 40 that had the same wing and horizontal tail as the SRM2 with the same moments and about the same drag profile. The SIG kits used different wings, non D-tube, and with other things in mind, we took them off the list. So only the Sky Raider Mach II and LA Racer 40 remained. This did give AirBorner Models / The World Models a monopoly of sorts, but they accommodated the needs. They added four solid colors of the Sky Raider Mach II, white, yellow, orange, red, and made some changes to the airframe in response to feedback that I and others gave to them. I pushed for the solid colors and I pushed for an ARC which was produced for a while, but the ARC did not sell real well. The ARC did eventually sell out as they are no longer available. You can turn a solid color into an ARC quickly as the solid colors come with CA hinges instead of being pre-hinged. The LA Racer came in four color schemes, but was made available in solid white and solid yellow. So there are currently 12 different color schemes to choose from for Club 40. With two airframes that have effectively the same drag profile, but with some style differences. The SRM2 has aileron torque rods. The LA Racer 40 has dual aileron servos outboard in the wing. I know that was long, but it helps to know where we came from and what we are thinking and it's 4am. ;)

I have focused on the [link=http://www.airborne-models.com/html/productdetails.asp?ProductID=21]P-51 Mustang G.S.[/link] because of P-51's being raced at Reno so much. Most people like or at least accept the P-51. The goal was to have a knowledge base about the airframe and consistency. Plus to have a choice in colors. The P-51 GS is available in 5 colors with solid yellow being one. I think if a class was formed and started working, TWM would produce a model that is not pre-hinged at the minimum with ARC a possibility. By staying focued on one airframe, any changes desired or needed are more likely.

They do have the [link=http://www.airborne-models.com/html/productdetails.asp?ProductID=55]Spitfire G.S.[/link] and the [link=http://www.airborne-models.com/html/productdetails.asp?ProductID=31]Zero G.S.[/link] in the same basic size. But if you open it up to those airframes, then should you open it up to others? I don't know. if you do, then it isn't a Spec class anymore.

As you have said on the engines, even if you have an engine list and require stock engines, people can still 'build' engines. In Club 40, the Thunder Tiger PRO 40 is the recommended and dominant engine. People do put time and effort into making their engines run the best that they can. I do. But the racing is still close and fun.

I know I have gone off-topic in my own thread. But if it helps define what I'm working on, then it helps me.

I am getting some help with this project though as some people find it interesting. The Miss America is going home with James Barr today who has already gotten the PTE36R and will be working with me on building, setup, and testing. He's already had his hands on the planes and is a great resource.

I appreciate the input here. That's why I posted the question.

RE: Experienced with the TWM P-51 GS?
 

Don. you may want to hop over to the pattern forum and look at the info there on the OS 33GT. One of the guys is running one and the power output looks really good.

RE: Experienced with the TWM P-51 GS?
 

I really would like to find someone that has one of the WM P-51 and could tell me what size servos they are running.<div>  <div>
<div>.</div></div></div>

RE: Experienced with the TWM P-51 GS?
 

Barry,

I talked to a local guy who had the Hitec HS-625MG High Speed 2BB Metal Gear Servo in a Zero G.S. that is about the same size and liked them. He used the SuperTigre G-2300 Dual BB Ringed w/Muffler in the Zero. I met him at the hobby shop the other day. He flies at a local field. I should have gotten his contact info, but I was buying one of these Ultra Micro Polecat and didn't get it.

RE: Experienced with the TWM P-51 GS?
 

James came to my house to get the Miss America today and brought his PTE36R.

We measured it and I took some photos. It is a good looking engine.

I found it on another web site and these guys seem to be equipped with parts. There are some videos at [link=http://www.troybuiltmodels.com/items/PTE36R.html]Pterodactyl PTE36R 36cc rear exhaust engine[/link]

RE: Experienced with the TWM P-51 GS?
 

I came into possession of a new and never run MLD-35 engine recently and have been preparing to use it on The World Model P-51 G.S. However, I may not use it. It weighs 2 pounds and 9 ounces without the ignition and mounting will be an issue. I have attached photos with it beside a Saito 180. The firewall would have to be cut out so that the carb would stick back into the fuselage with the length at the usable 6.15 inches. I would probably have to create a box to contain carb spray.

James Barr got the PTE36R for his Miss America. He had some issues with vibration on the test stand, but the vibration may have been related to the test stand. We don't know for sure. If you watch some of the videos, you can see that they do shake on hard mounted test stands. DLE gives warnings about using a test stand.

This page has some good info on the PTE36R [link]http://www.ibcinyourc.com/store.php?seller=carden540&navt1=55749&navt2=60028 &pd=4557781[/link]

The PTE36R only weighs 2 pounds and 4 ounces and has no firewall issues. Plus the rear exhaust is nice and fits right behind the cylinder and the firewall. it looks like the engine to get if the vibration is not too much of an issue.

I am probably going to hang the MLD-35 on the front of the P-51 without moding the firewall and see what the balance looks like.

RE: Experienced with the TWM P-51 GS?
 

I will be mounting the elevator servos and the rudder servo in the fuselage at the tail. And I will glue in the horizontal stabilizer even though it is designed to be removable. I will glue on the stab after everything is done and balance is close so I can add weight inside if needed. I may make a pocket so I can add weight easily on the opposite side of the rudder servo.

Luckily the engine mount blind nuts happened to be a perfect fit for the bottom standoffs on the MLD-35. So I was able to hang it right on front. It is not flush with the firewall, but 1/2 inch isn't going to make that much difference in the gross balance test.

I put the servos on the tail, in the boxes with hardware just because the boxes aren't much different than the horns and stuff that will be used. And I put the wing servos on top of the wing over their positions. I taped the belly pan on and the canopy. I also taped on the bottom rear cowl piece. Then I put on the cowl.

My son and I tested the balance and I was pleasantly surprised that there was still plenty of weight that could be added to the front. So I added the 13 ounce aluminum heavyweight spinner and still had half an inch to work with. The electronic ignition was not in place and there is no prop on it. But I plan to use a lighter eight ounce [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXMS83&P=SM]Dave Brown 5" Standard 2-Blade Aluminum Spinner[/link] if needed.

In terms of the carb sticking into the fuselage, there is a former about 3-4 inches from the firewall that was to hold the tank. It has three cutouts in it and I will cover those to form an airbox. I will put a velocity stack on the carb since there is room and I will put a scoop or openings into the airbox for fresh air. The tank will be mounted close to the CG.

At least now I know I can start working on doing things and I finally have little bits of time to get some work done on it.

RE: Experienced with the TWM P-51 GS?
 

I order the [link=http://www.sdshobby.net/new-mld35-pitts-muffermf35r-p-1958.html]MLD35 Pitts Muffer[/link] and the [link=http://www.sdshobby.net/drill-jig-specially-for-mld28-mld35-mld43-mld70-p-3826.html]Drill Jig Specially for MLD28 / MLD35 / MLD43 / MLD70[/link] along with a few other accessories last Sunday and they came on Saturday. Shipping via EMS was not too expensive and was quick.

I wish I had found this thread [link=http://www.rcuniverse.com/forum/m_9582932/tm.htm]MLD-35 Gasoline Engine[/link] before I ordered as it seems the stock ignition is not very good and it appears I need the RCEXL ignition if this engine is going to be reliable.

For what I will have spent on additional items, I could have gone with the [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXBCKA&P=ML]O.S. GT33 Gasoline Engine[/link] with the [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXAAUB&P=7]O.S. Standoff 5x44.5mm 1-3/4" GT55 (4)[/link]. However, I did not have the balance information and I did not know if the O.S. would fit.

Based on what I know now. I believe it will. I'm still not 100% sure, but I have looked at [link]http://downloads.hobbico.com/misc/osm/osmg1533-3-view2.pdf[/link] and at the MLD-35 with the Pitt muffler on the plane and I believe the O.S. will work. Maybe just some minor firewall mods.

I took the carb and reed valve body off the MLD-35 and put it on the P-51. I will actually use 1/4" spacers and move it out a little for clearance on the muffler. There is enough room on the cowl for an additional 3/8" beyond the specified 6.15" from firewall to cowl ring. I will still cut out the firewall for the carb and make an airbox around the carb.

One thing I have learned about gas engines is that you do not run them on a hard test stand. So I'm going to have to invest in a new [link=http://www.pspmfg.com/VibrationDampeningRCEngineTestStand.html]Vibration Dampening RC Engine Test Stand[/link]. I've wanted a second portable test stand anyway and I will use my current PSP stand on a metal sawhorse with a wood board.

RE: Experienced with the TWM P-51 GS?
 

I went looking for some TWM P-51 GS videos and I found some decent ones. I'm going to compile a complete list and add them to my site, but here are two I found very encouraging as they both use the DLE-30 and the flight performance seems quite reasonable for some giant scale racing.

One interesting comment about using Spring Air retracts instead. The included mechanical retracts seem ok, but the Spring Air units look really heavy duty. The 103HD set on this page [link]http://www.retracts.com/Retrax_100.htm[/link] looks like possibly the right choice.

[link]http://www.youtube.com/watch?v=lTRoJsuwLug[/link]

[link]http://www.youtube.com/watch?v=6KFRIyAga0g[/link]

RE: Experienced with the TWM P-51 GS?
 

Since I’m new to gas and if anyone else that may want to try this may be also, I’m going to continue to document what I do in the gas engine process as well as the radio installation as those are the parts that are different than the smaller planes. Different engines will have different issues, but James Barr and I are having the same engine questions, so others will likely have them also.

James is much further on this project than I am. He is almost finished with his Miss America. He is dealing with getting the spinner on his. The spinner that comes with the [link=http://ecsvr.com/abm/shopexd.asp?id=18]P-51D Mustang G.S. Miss America[/link] is a plastic spinner with an aluminum backplate. It has a socket head screw that goes to an adapter nut. The nuts that come with the spinner are 5/16-24 and a size up. I’m not sure what size. The screw that goes into the nut is an M6 on my aluminum spinner. I’m not sure if James’ is an M5 or M6. The screw is only long enough to reach the adapter nut.

On the gas engines that use prop bolts, the prop shaft typically does not have threads on the shaft. The prop is bored to fit on the shaft and the bolts hold the prop to the prop hub. In one of my previous postings I showed a prop drill jig. The jig is so you can accurately drill the prop bolt holes.

One the MLD-35, the prop shaft has an M5 – 0.8 threaded hole in the end of it. So If an M5 would hold the spinner, theoretically I could use a long M5 socket head screw direct to the prop shaft. The screw would need to be 95mm to 100m long. Those screws can be found, but they aren’t stocked in many locations. Ironically a 10-32 will screw into a M5 threaded hole. It has just a little wiggle room. I found some 4” long 10-32 screws. But I don’t think that even Loctite would keep them from coming loose.

On the MLD-35, the prop shaft is simply an aluminum sleeve that is actually threaded M10 on one end and M5 on the other. I took it off a couple of weeks ago before I ordered the Pitts muffler and the drill jig. They were only a couple of bucks, so I ordered 3 of them. I went to Monroe Hardware on Saturday and found some screws. One I found was an M6 x 90mm. I could drill out the M5 end of the sleeve and tap it for M6. I would have about 1/4” of thread. As it turns out, that is all that is in the sleeve anyway. I did not find this out until I drilled out a sleeve for 5/16-24 and tapped it. I had found some 5/16-24 set screws to use as studs in lengths from 0.75” to 1.5”. So now I can use the spinner adapter nut. I could also use a Dubro Spinner Nut on the test stand as I plan to start the engine with a low speed hi-torque starter.

In a trip to Lowes I found .75” steel spacers and M5 x 1.5” screws. I have the S1 PSP Universal backplate Adapter. I had to drill new holes for the standoffs as this engine does not use a standard rectangular pattern. But I got the engine mounted on the backplate adapter. With the spacers I can test with the Pitts muffler. I will actually use the stock muffler for most of the break-in as I don’t want to stress the Pitts muffler. The Pitts muffler is a little crooked, but that shouldn’t affect the installation.

RE: Experienced with the TWM P-51 GS?
 

I finally finished my Miss America. Got in the first flight.

Don has suggested that I do a build thread on the aircraft. I will give it my best shot.

I may not be the best writer but I am a very experienced pilot and builder.

James

RE: Experienced with the TWM P-51 GS?
 

Congratulations James.

I just read your first post on the build thread and you'll do a fine job. I see I will get answers to the things I have to do on mine.

I'm even more inspired to get mine done.

I ran my MLD-35 today. I did not wait to get the PSP Vibration Dampening test stand. My mounting post has some flex in it and I have a cushion at the bottom of the post. So I went for it.

I made up my gas can and tank yesterday. I made a holder for the ignition, switch, and battery last night. Only problem I had was that my 25/64" bit did not make a hole big enough for the prop shaft in the Xoar 18x8 prop. In the APC 18x6W I was able to get it on. I guess the wood is a little more resilient. So I had to go to Lowes this morning for a 13/32" bit.

After I got everything set up, I tried to start it. It only fired one time. When I ordered the Pitts muffler and prop drill jig, I ordered 3 extra hall sensors because I had read that some people had them bad out of the box. I changed it. Then it started right up. It took me a little while to get the adjustments reasonably decent.

I used [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXS626&P=ML]Klotz Gas RC Modelube[/link] and I mixed it 32:1 instead of 50:1 since the engine was new. I probably should have gone 50:1, or 40:1 at the max. But this gas stuff is new to me. Gas engines tune a little differently than glow engines. After tuning, I now wonder how well tuning would work with the vibration dampening test stand. But I also wonder how much stress the hard test stand puts on the engine.

I made a video of a run. The low end is rich as I was having trouble getting it to run leaned out, so I had a little trouble with the transition, but the video is at [link]http://www.youtube.com/watch?v=g1BLAzqqg60[/link]. I used a geared starter that I had bought for four stroke engines. It had no problem with this size of engine and I was only using a 7 amp battery.

I did choke the engine prior to starting. Did you set up a choke on yours?

RE: Experienced with the TWM P-51 GS?
 

I have at least 4 engines to run this weekend. One of them is the MLD-35 for P51GSR.

I was going to order the [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXBCKA&P=ML]O.S. GT33 Gasoline Engine[/link], but Tower is out-of-stock right now.

I was planning to order some stuff for the MLD-35 anyway as I have it and it seems very strong. Parts are cheap as you can see at [link]http://www.sdshobby.net/Wholesale/mld-35-is-1-sid-1.html[/link]. I see comments from people about sending in gas engines for service. This makes gas sound intimidating. Today I found out it is not so bad after all.

Because winds are 10-15 and skies are partly cloudy with a 10% chance of rain, I decided that I would do some engine work this weekend. I have several engines I had cleaned that need to get some test stand time. I set up a tent over my test stand sleeve on Friday afternoon so I would be ready for the weekend.

I ran the MLD-35 with different fuel. I switched to Pennzoil Air Cooled oil in a 30:1 mix (4.5 ounces to one gallon). I also switched to a 4.8 NiCd 100mAh battery. I have not gotten a new ignition yet. I was getting 8170 rpm on the high end and I was able to get under 2000 on the low end. After one adjustment things went south. I could no longer get the engine up to speed. I changed the mixtures completely, Then I changed the battery for another of exactly the same type. I still could not get it to run at speed. When I turned it over I was hearing a squeak. Not good I thought. So I took the engine off from the standoffs.

I took it inside and took off the spinner. Then I took off the cylinder and the back of the crankcase. Nothing appeared to have a problem. Everything looks good. I reassembled the engine and put it back on the test stand. But I switched to a 5 cell 2000 mAh NiMH battery. At first it did the same thing, but after about 30 seconds it started running properly. And it is a horse. I could get it up to 8200. But I backed it down to 7900. This is with a Xoar 18x8 prop.

I took some photos. I also took a couple of photos from the very back of my yard/field. I don't have the full 10 acres field anymore, but I can still fly electrics and 3D planes on the 3+ acre part that I have full control over. And the adjacent parts got mowed last weekend and this weekend. So I will be flying even more now.

Don't let the bigger size of gas engines intimidate you. They are actually more inviting to work on than the small engines, except the price of parts is higher. While I'm going to get the GT33, I think I'm going to see what I can wring out of the MLD-35.

BTW, we are staying with the 38cc max limit for [link]http://www.P51GiantScaleRacing.com[/link]

RE: Experienced with the TWM P-51 GS?
 

It is not the dampening test stand. And I need to get the vibration dampening test stand. I can actually feel the ground shaking at times with the MLD-35. Heck, I can even feel it vibrate with the glow engines at the right frequencies.

The one I have is the original version of [link]http://www.pspmfg.com/RCEngineTestStand.html[/link]

I'm going to get [link]http://www.pspmfg.com/VibrationDampeningRCEngineTestStand.html[/link] but PSP apparently took off for Joe Nall. There was a note on the web site a week ago Thursday morning as I was getting ready to order that orders after 10:00am would ship after 5/22. Also, the version of the dampening stand with the holder for the 3" wide big tanks is "Temporarily out of stock". I had bought two tanks. One for gas and one for glow.

I did not run glow engines today. I am going to take the test stand and the plywood holder for the ignition and battery off and run glow tomorrow. One thing that concerns be about the dampening stand is where do I put the ignition and battery. I used a 12" x 12" x 1/4" piece of plywood to hold the ignition, a switch, and the battery. I put it between the post and the test stand. So it is stationary with the engine. If I get the vibration dampening test stand and do the same, the ignition wire to the plug and the hall effect sensor cables will be flexing with every vibration. I don't like that. So somehow I have to find a way to use a holder for those items. The PSP site does not show that. They show the cables flexing. That is not something I want. That is also why I hesitated to get the dampening stand.

RE: Experienced with the TWM P-51 GS?
 

Thanks for answering my question Don.  I see we still need to do some research as I feel as you do to put everything on the same platform and have it all rattle the same. :D   You know what I mean.

RE: Experienced with the TWM P-51 GS?
 

I need a portable stand and will be calling PSP this week and asking questions.

RE: Experienced with the TWM P-51 GS?
 

Check out the stand in this video [link=http://www.youtube.com/watch?v=BHd3Rc8VoaM]O.S. GT33 Gasoline Engine - Low Idle Demonstration[/link]. It looks to be a 6" x 6" with cuts on it for what are called "Floor Flanges". I found them at Home Depot in the plumbing section along with pipe threaded to fit in 36" and 48" lengths. I bought the 3/4" size because that was all they had that matched up. Plus they looked to be the same as in the video except the ones I bought are galvanized. Lowes has them also.

You would get flex in the legs.

In some of the videos by these guys, they have a rope at the rear. I would drill a 1/2" to 3/4" hole through the rear and use a rope as a tie down. I'm doing that on a sawhorse test stand for the smaller engines.

I have a test stand, so why do I care. I'm not sure the PSP vibration stand is the optimal solution. Plus this seems easy to carry into the garage. I would still use the PSP backplates because it is hard to beat the pre-drilled mounting holes and the carb openings. I would possibly still use a PSP base (non-dampening) even on one of these 6" x 6" bases.

I am still focused on putting my plane together. I took the covering off the bottom of the open bays in one half of the wing to get a look at the wing structure this week. It is fine for the 38cc and under engines and I don't see a problem with it with those engines. I may or may not fully sheet the wing. At this point, I'm not planning to. I don't see the wing being up to 50cc engines without significant work and I'm not going to do that on this one.

What I am considering is Robart Retracts and RoboStruts. That is one reason I was taking a look at the wing. The primary reason was the consideration of 55cc engines for the racing class, but I also like the looks of the [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXET00&P=7]Robart Right Hand RoboStrut 3 3/4-4" Wheel 7/16"[/link]. I was going to order them and either the [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXMRR0&P=7]Robart 551RS 85 Degree Main Gear RoboStrut Ready[/link] or the [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXNCY1&P=7]Robart 701RS 85 Degree Spring Down RoboStrut Ready[/link], but the [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXES99&P=7]Robart Left Hand RoboStrut 3 3/4-4" Wheel 7/16"[/link] are out of stock.

RE: Experienced with the TWM P-51 GS?
 

I have decided to abandon efforts to get the MLD-35 working well enough to use in the P-51 for several reasons.

One, it may not be as reliable as other engines. I would be beating a dead horse and jeopardizing my plane. It may be fine with a new ignition, but that is more money and more risk.

Second, the [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&P=SM&I=LXZZH1]DLE Engines DLE-30cc Gas Engine Rear Carburetor[/link] is a good fit for this airplane and is a well known engine. It may not be quite as powerful, but it is a bolt in fit and will probably be the choice of many people who try this class out.

A [link=http://www.chiefaircraft.com/evo-30944266e.html]Tuned Pipe Silencer System[/link] is available for about $80 that should boost the power of the DLE-30.

I looked at parts for the DLE-30 at Tower and if you look at [link]http://www3.towerhobbies.com/cgi-bin/wti0005p?&I=DLEG0031&P=Z[/link] they aren't too bad with the exception of the ignition and I will likely try a different ignition anyway (Rcexl).

I had fun with the MLD-35. I'm glad I had it to play with. Especially since I did not have help from anyone in person and was going it alone.

RE: Experienced with the TWM P-51 GS?
 

<h2 style="color: rgb(0, 0, 128); font-family: Verdana, Arial, Helvetica; font-weight: normal; text-align: -webkit-left; "><font size="3">These are all the links to the</font><span style="font-size: 25px;"> </span><font size="3">RCPRO P-51 GS proposed rules, etc.  </font></h2><h2 style="color: rgb(0, 0, 128); font-family: Verdana, Arial, Helvetica; font-size: 18pt; font-weight: normal; text-align: -webkit-left; ">RCPRO P-51 Giant Scale Racing</h2><p style="color: rgb(0, 0, 128); font-family: Verdana, Arial, Helvetica; font-size: 14px; text-align: -webkit-left; ">Links to this page
www.P51GS.com
www.P51GSR.com
www.P51GiantScaleRacing.com
www.P51Racing.com
www.P-51Racing.com</p>