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-   -   Experienced with the TWM P-51 GS? (https://www.rcuniverse.com/forum/scale-racing-183/10914736-experienced-twm-p-51-gs.html)

DonStegall 10-21-2012 05:26 PM

RE: Experienced with the TWM P-51 GS?
 
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If you go with a 30cc to 36cc gas engine, don't go with an 8" pitch prop. James Barr used an 18x8 Xoar and was not getting enjoyable flights. Speed was part of it. Balance and tank position were part of it. But if you do a pitch speed calculation, you quickly see that the speed is not high enough. I have attached some screen shots. 8" at 8500 is only 65 mph. James went up to an 18x10 and got better performance. I think his ground RPM dropped to 7700. You will get 400-500 more with the 35-RA (I believe at the minimum). Plus there is unloading in the air.

The plane will not be a speed demon with a 30cc-36cc engine. But it will perform in the designed range. And the weight will be ok.

cjbotox 10-22-2012 12:30 PM

RE: Experienced with the TWM P-51 GS?
 
Thanks for the help and encouragement. Do you really think we need another thread? I'd do it but in retrospect I recall a lot of detailed info. I will continue to add MHO's to this thread and you sound like a very busy man so I'll try to keep questions limited to whatever unknown subjects haven't been covered, or present my own discoveries.

Off Topic: Your APP (s) are way too cool but my wife won't let me get a smart phone yet - she says wait for when they develope an app for detecting voice recognition lying... it's possible so don't laugh yet.

While digging around for a new DLE 35, I caught something interesting in the advertisements but NOONE can answer yet - about the rear exaust being set for a tuned pipe. What, where when can I get this information? So far I've been told it may take until next month for this news.

John

cjbotox 10-22-2012 01:48 PM

RE: Experienced with the TWM P-51 GS?
 
<span style="color: rgb(51, 102, 255);">James went up to an 18x10 and got better performance. I think his ground RPM dropped to 7700. You will get 400-500 more with the 35-RA (I believe at the minimum). Plus there is unloading in the air.

The plane will not be a speed demon with a 30cc-36cc engine. But it will perform in the designed range. And the weight will be ok.
[/quote]
</span>


I dunno, I would like to have a little bit of an edge but I have watched pylon racers using identical planes/engines and it seems that pilot skill, nerve and experience usually trump the 'speed' factor. I can't wait to see this plane zooming in on low passes like the one seen in India.

John


DonStegall 10-24-2012 04:53 AM

RE: Experienced with the TWM P-51 GS?
 

ORIGINAL: cjbotox
...

While digging around for a new DLE 35, I caught something interesting in the advertisements but NO ONE can answer yet - about the rear exaust being set for a tuned pipe. What, where when can I get this information? So far I've been told it may take until next month for this news.

John

I've seen information about it on a site, possibly the Australian site. The engine is set up for a tuned pipe and one of the bonuses touted about the rear exhaust is that the pipe can come straight off the rear on pattern planes.

I think a pipe on the rear exhaust will be difficult on the WM P-51 GS.

I have the O.S. GT33 for my yellow plane. I got a DLE-30 for my Double Trouble knowing the DLE 35-RA was coming out because I planned to run a tuned pipe on the DLE-30. I kind of wish I had waited for the 35-RA. But I haven't run the DLE-30 yet and it may get sold as NIB as I have only taken pictures of it.

cjbotox 10-24-2012 06:01 AM

RE: Experienced with the TWM P-51 GS?
 
Thanks Don, since I don't have possesion of plane, WAIT...the store just called, it's in! Oh boy - woo hoo! Now to make the Looong drive.

Anyway, to your point - you may be right about pipe installation. Unless I can figure another mounting position the pipe would interfere with wing install, etc, etc. The DLE 35 should be plenty with stock muffler and high pitch prop as you suggested. I was just over in Jim's thread and watched the video - I think you all did the right thing by limiting engine size to this airframe. According to Jim's comment on C of G the plane had some scary tendencies if not balanced right. Asked him some questions on this matter.

I will keep you posted with my progress and thanks again for answers!

John


airraptor 11-04-2012 08:00 PM

RE: Experienced with the TWM P-51 GS?
 
We are thinking of getting these to run at our club. how would the DLE 55 fit in it?

cjbotox 11-05-2012 09:15 AM

RE: Experienced with the TWM P-51 GS?
 
I'm sure Don will weigh in on this question eventually, but here's my 2 cents: This forum is being built on requirements of the RCPRO rules for expanding a new line of racing developed on the successful Club 40 racing. Incidentally, I live only 36 miles from where this precept was born in Ocala Florida. I believe the concept will be just as contageous and this is one of the reasons I'll be staying inside the parameters, I know there'll be some up-coming competitions I could compete in locally. But before I knew this, I too searched for suitable engines for TWM P-51 Mustang, leaning towards high powered glow engines. I will now be purchasing a DLE 35 because it fits inside cowl perfectly and has rear exaust. I hope to have a powerful but reasonably light airframe, hopefully light enough to utilize stock retracts. There are allowed mods you can do to spec engines which might give you an edge but remember this is a pretty close scale MUSTANG and so it has some inherent qualities that one must be considerate of before pushing the manufacturers limits. I personally have not heard or seen this model with a 55 in it, so if someone out there has been flying this combination, drop me a line. There are other suitable Mustangs like the TF Giant Mustang and many more out there.

I found another thread a while back, you should read last post:<span style="color: rgb(0, 0, 255);">http://www.rcuniverse.com/forum/fb.asp?m=11095780</span>. There's a lot of yes and no answers to your question, but its doable. I don't want to stray from this forum's precepts, but I'll just throw in a couple quick answers based on what I've heard- let me stress heard because as I said I have yet to see the 55 installed and flying successfully and flying at least a year.

Yes - if you don't mind asthetics. You'll end up with less then half the front cowl (see build thread RC groups WMP-51) I've also taken specs for mounting the 55 off web sites, its gonna be tight!

Yes - if SUPER-REINFORCE entire front fuse from firewall to wing mount bulk head AND don't forget refitting landing gear and erinforcement.

Yes - if your not afraid of afore mentioned tendecies in a model that will weigh in with a higher wing load.

There are many more considerations, but I'm gonna stop here because in consideration to the author of this forum you will have to look somewhere else and find someone who HAS successfully built and flight tested this set up.

Good luck and let me know what you find.

John



DonStegall 11-05-2012 10:44 AM

RE: Experienced with the TWM P-51 GS?
 
Based on an exchange with Marty Flood about the USRA Provisional Warbird class, I took the covering off of the open bays on half of my Rockwell wing. I looked at the spars and the shear webs. The shear webs are only on every other bay. With the open bays and the shear webs as they are, I don't recommend trying to use 50cc and above engines on The World Model P-51 Mustang G.S. for pylon racing. Maybe gentle sport flying. I could be wrong. But personally I would not want the liability. Pushing the plane beyond what a 30cc - 38cc engine can do in my opinion is too risky without adding proper vertical shear webs and sheeting the open bays. Then you get into wing loading issues.

The [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXEDP2&P=ML]Top Flite Giant P-51D Mustang ARF 2.1-2.8,84.5"[/link] is built for 50cc - 55cc and above engines.

At some point in the future, The World Models P-51 Mustang G.S. may be built with a more appropriate wing for higher power. But that is not in the near term according to the information I have.

The DLE-55 will fit with a length of 6.69" from thrust washer to back of the stand-offs. As long as you don't go over 6.75", the cowl fits length-wise. The manual for the DLE-55RA is not online anywhere that I can find at the moment, so I can't say for sure about it.

One thing you could do if you allowed the DLE-55 is specify the prop. If you kept the pitch down to 10", you could limit the speed.

But of course, as the previous response alludes to, I would like to see you use the RCPRO Proposed Rules at [link=http://www.rcpro.org/content/rcpro/p51gs/rules/default.aspx]RCPRO P-51 Giant Scale Racing - Rules[/link].

airraptor 11-06-2012 09:16 AM

RE: Experienced with the TWM P-51 GS?
 
We are looking at this plane at our club since a lot of the guys fly the smaller one. We had talked about the little 30-38cc engines but didnt want a slow plane. if it can fly along at 100 or so would be ok. We have flow some of the 60 size mustangs from other MFGs like horizon and TF and the best was my H9 miss america at around 115-120 with a DLE 30 on a 15x14 prop. the plane was around 8.5 lbs

All of the WM wings are made that way. I strip the cover off all my WM planes and recover so that the plane will last. I am very good and reinforcing these planes or any arf to withstand what ever engine I throw in it and still keep the plane light. I could build one of these up to handle a DA85 on pipe if needed.

I would like to keep close to your rules so that if it catches on out here we can just drop right in. ;)

cjbotox 11-14-2012 08:41 AM

RE: Experienced with the TWM P-51 GS?
 
Don; have you finished sheeting the wings yet? If so, how did you remove rib caps? I'd like to add thanks for choosing this model, make and company. I have nothing but good things to say about thier quality to value and customer sevice. The reason I ask is I'm sure by this time next year I'll do a make over.

John

airraptor 11-15-2012 11:39 AM

RE: Experienced with the TWM P-51 GS?
 
Don I will be odering some mustangs here soon. I will start build in mid december time frame. once I go through the plane I will work on the Gold race stuff for these.

cjbotox 11-15-2012 12:30 PM

RE: Experienced with the TWM P-51 GS?
 
<span style="font-size: small;">

Don I will be odering some mustangs here soon. I will start build in mid december time frame. once I go through the plane I will work on the Gold race stuff for these.</span><span style="font-size: small;">
</span>


What is Gold race stuff?

John

DonStegall 11-15-2012 02:09 PM

RE: Experienced with the TWM P-51 GS?
 

What I had in mind was possibly adding a Gold class when The World Model starts producing the G.S. with the reinforced wing.
I wrote this in an email.

There is currently a farily large stock of the current P-51 Mustang G.S. design in the various colors. There is a possibility that future production could have better reinforced wings that are fully sheeted.

Then they would hold up to the 55cc engines out-of-the-box.

I decided not to sheet my wing as I'm putting the O.S. GT 33 on it. I also have a Double Trouble that is not started.

The 30cc to 38cc engines keep the wing loading in the recommended range and the speeds in the more manageable range for the majority of fields. I was going to designate this the Silver class.

If the class takes off, I can see some groups wanting to run a faster version on longer courses. I planned to designate this the Gold class.

Now that the topic is out, we can talk about it. Don't worry about the build thread. This is a multi-purpose thread.

DonStegall 01-19-2013 10:37 AM

RE: Experienced with the TWM P-51 GS?
 
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I'm working on covering the fuselage and tail this weekend.

I have half of the fuselage done now and I hope to finish the fuselage today.

I will have a fair amount of painting of fiberglass parts to do, plus the canopy. But at least I'm taking another step.

MFLOOD3800 01-19-2013 04:42 PM

RE: Experienced with the TWM P-51 GS?
 
If the class takes off, I can see some groups wanting to run a faster version on longer courses. I planned to designate this the Gold class.

Now that the topic is out, we can talk about it. Don't worry about the build thread. This is a multi-purpose thread.



I think the idea of a Silver Class and a Gold Class is awesome Don.
Sometimes the right ideas are so simple we all miss them.

This will allow many who want to "wade" in to try it and others who want to "jump" in to go for it.

I look forward to hearing more about this concept.

Ive been talking to a few about it and the response is split.

1. A few really like it and have built some (4) 50cc size warbirds. ABout $1500 plus a lot of reinforcing "time"
2. Some have resisted due to the cost ($1500+) and dont want to invest that to "try" racing.
3. Some who have planes already have liked the idea and some dont want to risk their scale "pride and joy" in racing.

I really feel to try and capture new people is a great idea. But the reality is, at these prices and skill sets, the audience to be captured may be "Racers" already racing who desire to step it up.

Just my take on this.

DonStegall 01-20-2013 05:46 AM

RE: Experienced with the TWM P-51 GS?
 
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Marty,

The 38cc reed valve limit will keep the speeds down to 110 mph or so. 120 at the absolute max. I think 100 mph is more like it. And that is a fine speed for bigger more complex airplanes with retracts and gas engines with ignitions. We are not placing any limits on exhaust systems, so tuned pipes are allowed. Engine modifications are allowed, so porting and polishing are ok. Yes, that does open it up to a little bit of a horsepower race, but policing those kinds of changes is nearly impossible and it adds a little fun to the game. These engines are big enough that opening one up and working on it should not be scary. With DLE-30's and copies under $300 there are plenty of choices to play with. The new DLE 35RA should be a good engine as is.

A Gold class would up the speed significantly, and the airframe prep would go up. We have to think about whether or not to keep it just The World Models P-51 or allow the [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXEDP2&P=ML]Top Flite Giant P-51D Mustang ARF 2.1-2.8,84.5"[/link].

I finished covering my fuselage on Saturday. I'm going to do the tail today.

BarryReade 01-20-2013 07:17 AM

RE: Experienced with the TWM P-51 GS?
 
It is looking good Don.  I hear that someone has ordered a 35RA ro replace a real dog that they had.  It should be interesting to see how it does.

DonStegall 01-20-2013 09:40 AM

RE: Experienced with the TWM P-51 GS?
 
1 Attachment(s)
James reported yesterday that the DLE 35RA was sweet on the test stand. I hope it works out well for him.

I basically finished the iron on covering of the fuselage and tail today. Took a few photos of the plane snapped together. Should look pretty cool in the air. ;)

BarryReade 01-20-2013 01:14 PM

RE: Experienced with the TWM P-51 GS?
 
Well, hopefully you will be able to see it!!:D

MFLOOD3800 01-20-2013 02:06 PM

RE: Experienced with the TWM P-51 GS?
 
That plane is "Loud". Pylon judges will see that one- better not cut Don!!
:)

DonStegall 12-01-2014 03:23 PM

8 Attachment(s)
I'm back at work on this project. I've had a lot of more pressing things.

I have worked with the Robart 701RS retracts and by using Robart Aluminum Air Line Restrictor (4) I can control the retract speed. Robart has new electric retracts that should fit, but I'm going with what I have on this one.

I got my MACS header today and it looks like it will work. I probably could have gone with the 4211 Long that extends out a little less that the 4212 Ex-Long. But I don't have the pipe yet so I don't know. The hole in the cowl will be small enough that I can change if I need to.

We are going to make changes to this proposed racing class. It will be opened up to WWII Warbird fighters and Reno Unlimited racers with at least an 80" wingspan and the engines will be 40cc or smaller reed valve engines.

DonStegall 01-02-2015 03:41 PM

1 Attachment(s)
I got my MACS 1196 Tuned Pipe and it slips on the MACS 4212 Ex-Long Header. Should make tuning easy. You cut the header after getting the tuning right. It will then tuck right beside the fuselage and clear the wing easily.

I have all the parts for this plane now and should have it flying in the spring or early summer. I have a lot of painting to do on the fiberglass parts and the canopy.

DonStegall 01-23-2015 05:00 PM

1 Attachment(s)
I'm getting started back on this project. I have some of the hard work on the fuselage done except for the painting. The engine is fully mounted with the velocity stack chamber and the servo mountings are in the tail. Still have to mount the cowl pieces and get them ready for paint. Most of the work I have left is on the wing and retracts.

If we get some decent weather any time soon, I'm going to get the engine on the test stand with the pipe. Need to see if I'm going to get booted at the local clubs for noise or if I have to fly up at Old Julian until I get a MACS Quiet Pipe to have as an alternative.

I'm going to video record the remainder of the build and the engine testing. First thing I need to do is make a stand that can hold this thing on the bench.

For some pictures of the real airplane, go to http://www.mustangsmustangs.com/p-51...erial/44-74506 and http://www.mustangsmustangs.com/p-51...erial/44-72902

BarryReade 01-23-2015 06:23 PM

Don, I made one of pink foam from HD.

http://marauderer.smugmug.com/Airpla...DSCF4117-M.jpg

I have more pics if you need just ping me.

DonStegall 01-24-2015 01:21 PM

Thanks Barry.

I made one today after using the foam cutter and my Quickie wing jig to make some easy cuts.

Mine's not as nice as yours. But it should get the job done.

After my most recent eye doctor appointment, I finally have good eyesight again. We made some tweaks and my astigmatism had changed. I can see the leaves on the trees across the field now. When I have my distance contact in my left eye. And I can read the computer screen easier now as well. So I've been getting some RealFlight time and with the Club 40 NATS being held in Muncie this year, I'm really pumped to get back to flying on a frequent basis.

I'm finally ready to get this big Mustang in the air, even if I have to take it up to Old Julian to fly it. I have a feeling the engine is going to be pretty loud with that MACS tuned pipe on it. Boy are the neighbors going to enjoy my test stand running this spring.

I made a video today and it is at

http://youtu.be/FTesLUhhRvc


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