DonStegall

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Tower Hobbies has brought the price of the [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&P=SM&I=LXZZH1]DLE Engines DLE-30cc Gas Engine Rear Carburetor[/link] down to $284.99 and with the $50 for Super Saver members for orders over $299.99 when you order the [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXBAFJ&P=M]DLE Engines Propeller Drill Guide DLE30[/link], you have an engine for $250 for [link=http://www.P51GSR.com]P51GSR[/link].

The [link=http://www.troybuiltmodels.com/items/DLE35RENGINE.html]DLE Engines DLE-35RA Rear Exhaust Engine[/link] should be coming out soon, but running a tuned muffler or just a header on it will be an issue. Getting it under the cowl will be nice though and the improvements sound good. It does not have the same mounting pattern as the DLE-30, GT33, and PTE-36R though.

I got one of the DLE-30 engines for my Double Trouble. I test fitted the muffler from the GT33 because the muffler bolt pattern is supposed to be the same and I plan on testing the tuned pipe I have on the GT33 on the DLE-30. It fits perfectly. So any DLE-30 exhaust systems should work on the GT33 and vice versa. THE DLE-30 is light compared to the GT33 and since I plan to put the elevator and rudder servos in the radio bay instead of in the tail, it should work out fine.

DonStegall

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I ran the GT33 with the [link=http://www.horizonhobby.com/products/silencer-system-complete-26gt-gt2-gx-EVO30944266E]Silencer System, Complete:26GT/GT2/GX by Evolution Engines[/link] on Saturday 6-30 on my tripod test stand.

The video is at [link]http://www.youtube.com/watch?v=5aHn7uMxCnM[/link]

My test stand area is 150-200 feet from my house. The test stand is a little bulky to carry that far, so I put in in the back of my truck and transported it that way in the 100+ degree heat. I could have taken the legs off, but it was easy to put in the truck and at low speed it was fine.

I got 8650 to 8710 RPM with the pipe. I did not tweak the engine to the max. I did have a tank problem from leaving the engine out in the heat all day and the tygon came off of the fuel pickup in the tank. I readjusted the engine and actually got as high as 8760 with it running even smoother than in the video.

This seems like a very solid engine and I'm looking forward to completing my BARDAHL Miss. I've actually been getting some work done on it and will be posting about that soon.

DonStegall

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I finally ordered and received the servos I'm using in the Bardahl Miss. I'm using [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXZTZ2]Hitec HS-5685MH High Volt High Torque Metal Gear Servo[/link] because I am going to use LiPo receiver batteries and I wanted a reasonable speed at a reasonable cost.

I'm putting the elevator and rudder servos in the tail. The newer models of the P-51 G.S. use pushrods, but the older version used pull-pull for elevator and rudder. All of the yellow Rockwell kits that AirBorne has in stock and all that they will have for some time are the older model. The Double Trouble is the newer model with the new tail. That is why you will see differences between Barry Reade's build and mine.

I made servo trays out of 1/4" aircraft plywood. Yes it is a little heavier. But they only weighed .1 ounces (actually the scale showed 4 grams for one of them). I cut the hole for the rudder servo first and installed it using 30 minute epoxy mixed with WEST SYSTEMS 403 MicroFibers. I generally use the microfibers instead of cabosil for wood joints as the bond is superior and the 403 is thixotropic.

I will be recovering the fuselage, so I want to get most of the work done now.

After installing the servo trays and letting the epoxy cure, I filed the holes to size so that the servos would fit. I then hardened the mounting pad area with thin CA. Then I sanded the raised balsa grain.

DonStegall

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I was asked what thixotropic means. Go to [link=http://www.systemthree.com/sys3news/?p=113]SECTION VII C – MODIFYING EPOXY WITH FILLERS[/link] of the [link=http://www.systemthree.com/sys3news/?cat=6]The Epoxy Book[/link] to learn more terminology about fillers in epoxy and maybe pick up some tips.

DonStegall

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The fuselage is stripped and ready for re-cover, or more work. I kind of want to do the covering, but I also need to mount the engine.

3136

Hi Don, how did you manage to strip it so cleanly? I have the ridge runner version and whenever I need to fix up little bits of covering I find that a clear layer peels away leaving the silver behind. TWM covering is nothing like solarfilm, that stuff peels away in one piece.

DonStegall

My Feedback: (1)

If the covering is damaged, you will have problems getting it off cleanly. The best thing to do is to remove the film and then use acetone to remove the adhesive / color. Just be careful where the good covering is or you will damage the adhesive on it. Acetone takes the residue right off. And you can use acetone to remove CA and epoxy from ToughLon without hurting it much as well. I clean up after gluing with acetone all the time.

If the covering is not damaged, a heat gun is your friend. Just get the covering lifted up a little and use a flat concentrator tip and use just enough heat to get the adhesive to let go. Try not to burn your fingers. This makes stripping MUCH easier. You do have to be careful on control surfaces or you can warp them.

Finally, strip in multiple paths as needed. Use an x-acto to split the covering you are removing into manageable sections.

DonStegall

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My next task on the fuselage is mounting the engine. The mounting holes and blind nuts in the firewall are for a beam mount. They do not line up for the gas engines.

Barry Reade had taken the top part of the engine box off and it gave him easy access to the back of the firewall. Plus he was going to be able to do additional reinforcement. I really liked this approach, so I decided to follow suit. The top of the engine box is light plywood and the angle pieces are hard balsa. I used a 1/2" chisel and removed the balsa. This gave me easy access to remove the plywood.

After removing the top of the engine box, I mounted the O.S. GT33 using one bolt and placed the cowl on so I could see where I will need to mount the engine. The single bolt held the engine in place just fine and I can see that I need to drop the engine down 1/4" and to the left 1/8" after I get the firewall prepared.

I removed the blind nuts and sanded the back of the firewall. I drilled out the holes for 5/16" and made some plugs out of 5/16" dowel. I left them a little long as grinding them will be pretty easy from the outside. I glued them in with epoxy. I brushed in epoxy into the holes and on the plugs, then put some epoxy mixed with micro fibers on them and inserted them. On the back of the firewall I smoothed out the cavities left by the blind nuts and other divots with the epoxy and micro fibers.

All of this was much easier with the top removed. I will also add chopped carbon fiber to the joints of the bottoms of the firewall and sides while I have it open.

3136

Thanks for the tip about the heat gun Don.
I have a dle 30 in mine, I think the os 33 would be a better choice. From what I have seen at the field they have a lot more grunt.
The muffler supplied is also much more effective than the dle 30.
I'll be interested to see your results.

BarryReade

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Don, it's starting to take shape and really looking good.

DonStegall

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MACS Products is supposed to have a tuned pipe header that fits the DLE-30 now. I'm going to order one soon. I'm also going to order one of their pipes. I saw over 400 rpm gain with the Evolution pipe I got from Horizon and I don't believe it is a full tuned pipe and that I'm getting maximum gain. I haven't had time to put my DLE-30 on the test stand. When I do, I will let you know about the performance gains with the pipes.

Thanks Barry. I have a long way to go. Your thread has been a great benefit to me. Seeing you march through the engine mounting got me inspired. And since I had to miss the Tuscaloosa race due to work, I tried to get something somewhat fun done this past weekend.

James Barr's video also inspired me to get going. With people seeing that the plane performs well even though the speed is not tremendous, I think there will be more interest in the racing class.

DonStegall

My Feedback: (1)

I ground and sanded the plugs in the firewall flush. Then I made a template for the engine mounting holes in Visio and printed it. I attached it to the firewall and drilled the holes. After mounting the engine, the placement looks very good. Of course with the cowl being held in place with small screws, I will have to be careful about how I place the cowl.

I used the O.S. Standoff 5x44.5mm 1-3/4" GT55 (4) and with the 1 3/4" stand offs the stock muffler just about has enough clearance. With these standoffs, there is an extra 1/4" to 3/8" of space that you can move the cowl out. I will show how using 2" standoffs means no grinding to fit the stock muffler in another post.

DonStegall

My Feedback: (1)

I will be using a tuned pipe on this engine and plane. I have documented this pipe in the "Experienced..." thread. I'm going to be getting the header and a pipe from MACS Products.

But you can see how the pipe fits just right and will nestle right over the wing with about 1/2" to 3/4" of clearance when it is close to inline with the thrustline.

DonStegall

My Feedback: (1)

If you used the O.S. Standoff 5x50.8mm 2" GT55 (4), the stock muffler will fit right on without grinding, except for heat clearance.

I had some 1/4" spacers from PSP (http://www.pspmfg.com/RCStandOffsMotorSpacers.html) and by using them to bring the engine out to 2", the muffler bolted on fine. The cowl would still have to be cut out to fit the side of the muffler, but the can of the muffler would fit tucked behind the cylinder.

I may use the 2" standoff spacing as I am considering using a velocity stack. If I do, I will have to cut out an opening in the firewall and make a box or some kind of container to isolate the engine compartment from the inside of the plane.

DonStegall

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I want to be able to use a velocity stack on the GT33 (or DLE-30) in the Bardahl Miss.

Here is an aftermarket velocity stack installed on the GT33 and you can see that it sticks back behind where the standoffs will mount to the firewall. Even if using 2" standoffs, there has to be an opening in the firewall. And gas engines spit from the carb, so the opening has to be sealed off. Part of the very reason for using the stack is that spit. The stack contains part of it and keeping it in the airflow results in slightly more power. Whether or not I actually use the stack, I have to make accommodations now if I want the capability.

The stack is 1.325" at the widest part of the bell. I drilled a 1.75" hole in the firewall using a hole saw. First I actually made a ring using a 2.125" hole saw in some 3/8" plywood to see if the hole would be too big. I decided that it would weaken the firewall too much, but that I could still use the ring as my extension of the hole for the cavity for the breathing of the intake. I will back the ring with 1/8" light plywood. I opened up the hole in the firewall a little with a Dremel just for a little more breathing room.

I can't imagine trying to do this work without having taken the top of the tank compartment off. So my hat's off to Barry Reade for showing that.

DonStegall

My Feedback: (1)

I mixed up a shot of WEST 105/206 which is just under a fluid ounce and an ounce of weight and mixed in 1/8" chopped carbon fiber.

I applied the mixture to the inside of the fuselage at the bottom front of the firewall and back down the sides to the first former. This should add a lot of strength in that area. I used a spatula to get the CF in place, then used a 1/2" acid brush to smooth it out and press it into place.

I will still pin the firewall on the sides and top as Barry is planning to do.

BarryReade

My Feedback: (1)

Well, it looks like the easy part is done.  I am about at the same point of build that you are .  I was thinking of building a fiberglass/epoxy dome cover to install on the back side of the firewall with a small drain hole to drain the carb spit and that would seal up the velocity stack  while allowing enough airflow to the carb.  The dome would be large enough to drill at least four 1/4" hole through the firewall to give additional airflow.

DonStegall

My Feedback: (1)

The top of the tank compartment was 1/8" or 3.5mm lite plywood. Barry has concerns about the OS GT33 ignition module fitting on top of it, but I don't think there is an issue as these pictures show.

The original piece of plywood weighed 0.8 ounces. I made a new 1/8" aircraft plywood piece and it weighed 1.2 ounces before I cut a hatch into it. I will use the hatch to get inside the tank compartment area if needed. I will use light plywood as the hatch and the weight gain will be minimal. I can get my whole hand into the hole. There is enough material at the front to add strength to the firewall and I will use chopped carbon fiber like I did around the bottom, plus I will pin the plywood to the firewall in 2 to 4 spots. The angle will be made of 1/8" aircraft plywood as well. So the nose should be sturdy.

With all three of my tail servos in the rear, I have a little more ability to add weight in the front than I would have had otherwise. But I'm still trying to keep it down. And since I don't have two retract servos up front that is another issue for weight up front. With the tuned pipe instead of a muffler, that is also a factor in allowing me to reinforce as I see fit.

I will complete the velocity stack cover, then do some more work on this area, and hopefully get the engine compartment wrapped up in a week so I can cover the fuselage.

DonStegall

My Feedback: (1)

I had made a ring out of 3/8" plywood with a 2.125" hole in it and I covered it with 1/8" plywood. After putting the engine on with 1.75" standoffs I didn't think the airflow would be sufficient. I may use 2" standoffs, but I wanted the option of using the shorter standoffs. So I made a new "airbox" using three pieces of 1/4" basswood laminated after cutting the 2.125" holes with a hole saw in a drill press.

The new airbox came out 0.6 ounces where the shorter one was 0.5 ounces so the weight was a marginal gain over what I started with.

I glued it in and clamped it in place.

DonStegall

My Feedback: (1)

Here is the completed velocity stack enclosure. I'm happy with the way it came out. Even if I don't use a velocity stack, I gave it a shot. I'll just have to see how the engine runs with and without it in the plane.

I can put the lid on the tank compartment now.

DonStegall

My Feedback: (1)

Since I will probably mount the ignition module on the hatch cover, I decided that I needed to make the compartment top robust. I made corner pieces out of 1/8" light ply and glued them to the top. I drilled holes for 4-40 screws in the top and hatch, then put 4-40 blind nuts in the corners. I CA'd them with thin, then medium so hopefully they will stay in place.

I was going to glue the top on, then make the angle side pieces. I've decided to try to make the angle side pieces and glue it all together at once. I will tilt the bandsaw table to make the angle cuts instead of trying to sand them to fit.

BarryReade

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Great attention to detail Don.  It is really looking good.

DonStegall

My Feedback: (1)

Thanks Barry.

I cut the side angle pieces by tilting the bandsaw table to 45 degrees. It is a little tedious cutting straight at that angle, but I use a metal cutting blade in my bandsaw and that makes cutting reasonably thin plywood and balsa easy. My bandsaw is a tabletop model that I have on a stand. One of the $100 Delta variety.

Here is the completed front end. I glued everything together with WEST 105/206 and microfibers. I may add some chopped carbon fiber on the inside if I have enough access, mainly to the front area. I don't think I'm going to pin the firewall with the way it is already interlocked on the sides.

cjbotox

My Feedback: (11)

This is verrry interesting! I just ordered a WM gs Rockwell from LHS after selling off some planes I was tired of. While searching for BEST ENGINE suited for this plane, I came across this thread - exciting!! I've decided to go with DLE 35 even though I've been trying to stay away from gas. I want to stay within parameters for RCPRO racing. My only experience with pylon racing has been with my old .15 powered Sig Wonder - I bring it out to fly even though only 2 people have raced against me in last year. Our club has 2 pylons set for Q 500 - not sure of distance but plan on asking.

First question: What do you use for C of G balancing; can I use fingers? I DON'T want to spend $100.00 on an EZ balancer that I'll only use a couple times. And no, my friends are all flying electric stuff so I don't know anyone I could borrow something for a 15 lb.+ airplane.

The club I fly at has grass runway, how long will supplied gear last? I'd like to try and utilize them as long as possible since they're probably the lightest system.

Has World Models done anything to beef-up landing gear mounts? I've heard that earlier versions had issues with some flimsy stuff?

When banking smaller versions (.46 size) mustangs, the G force allowed them to drift/sink/slip outwards. My hershey bar Wonder tracks rock solid, especially in a fast bank around pylons. I hardly loose any momentum when 'returning'. I realize all planes have different characteristics but this will help me decide about racing.

Does anyone know the lengths for standoffs in this plane for a DLE 35?

I am planning to join RCPRO after finish and flying - any meets here in N Central Florida?

John

DonStegall

My Feedback: (1)

Glad you found the thread. I will post more comments later. I have some stuff I have to do today and tonight, but I may get a few minutes.

Check out this thread as well [link=http://www.rcuniverse.com/forum/m_11061188/tm.htm]Gas Powered World Models P51 GS[/link]

The retracts requite some attention if you use the stock retracts. The stock pushrods are not appropriate at all. And you need a high powered servo for each. The Hitec 75 will not be strong enough. The [link=http://spektrumrc.com/Products/Default.aspx?ProdID=SPMSA7000]Spektrum A7000 Retract Aircraft Servo[/link] or the high voltage [link=http://spektrumrc.com/Products/Default.aspx?ProdID=SPMSA7040]A7040 HV Retract Servo[/link] are end-point adjustable and speed controllable if you are using a TX with those features. DX-8, JR 11X, etc

The [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXCPZC&P=ML]DLE Engines DLE-35cc Rear Exhaust Gas Engine w/EI &Muffler[/link] should be a great engine for the plane as many have used the DLE-30. The thrust washer to rear of the standoffs is almost the same length and will work fine with the stock standoffs. You can use anything with a length of 6.1" to 6.75" without a worry on the cowl.

I'm just now getting started back on mine.. I'm going to try to cover the fuselage over the next week or two. And I'm going to be working on my retract installation. I have to get some parts for that. I need some Robart air Tees. I have some other wing work to do with the surface servos and control rigging.

I encourage you to do a thread. We can always learn from others and I like to see how others do things. I picked up ideas from Barry Reade and his thread at [link=http://www.rcpro.org/net/ThreadView.aspx?threadid=1091]WM P51 GS Double Trouble Build Thread[/link].

Work has had me covered up for the past couple of months (at the minimum) and I have another project on a deadline. Hopefully I can get some time to do some modeling. But at least I have a job right now. So I consider myself lucky.

I have to admit that I've been a little distracted by my Android application development and publishing on Google Play and Amazon Appstore. My RC Calculators app was a lot of work to get to a state to publish. It was a personal goal to get that thing into the marketplace. Then I added drill size charts to it. I decided to do a standalone [link=https://play.google.com/store/apps/details?id=com.donstegall.drill*****art]Drill Bit Charts[/link] application because the other apps out there were not as easy to use as I thought a simple reference chart could be. Drill Bit Charts is getting installed a fair number of times every day. It has gone well past the R/C modeling community. I work on RC Calculators most every day on adding new features so that takes time away from working on airplanes.