9. Top Flite P-51D Build Log – DLE-20cc Gasoline Engine Conversion (Updated 8/11/2012)

I have the plane and it’s in the queue after the Extra 260 gas conversion, then the P-47 gas conversion.

From all I’ve read, the DLE20cc gasser will replace all my 4-stroke glow engines.

20cc Gasolina!

2/19/2011 – DLE-20 is on its way. I’ll start the basic build and when I get to the conversion part I’ll show the steps.

2/23/2011 – The build is progressing. The wing is joined and now I’m just waiting for the E-flite electric retracts to finish it.

E-flite 60 – 120 90-Degree Main Electric Retracts.

2/23/2011 – Received the retracts. They look good and are almost a straight drop-in. I’ll have to remove a bit of balsa and remove the push rod tubes to run the servo leads through the wing.

2/25/2011 – Installed the retracts. The retract mount area requires a bit of clearance and I used a drum sander on my Dremel for that.



…Done. Well, just need to trim the gear wire.

The hard part was running the servo leads through the wing. To accomplish that I carefully removed the existing mechanical retract push rod tubes and then fished a 14″ servo wire extension (no connectors) through the opening. Then I installed connectors onto the servo wire.

Crimping tool, buy the best you can afford. This cheap one ($15) made the job harder. I recommend the one seen in the video below.

I’ve never “crimped” before and was having a difficult time with it, so I looked up a How-To-Video. Boy was I doing it the wrong way!

2/26/2011 – Got the engine mounts (temporarily) mounted. They will need to come off a few times during final installation due to the top of the fuse completely covering the bottom of the engine.

Note: For clearance, some of the former just below the front of the engine mount needs to be removed. Again I used a drum sander on my trusty old Dremel for that.

Former material needs to be removed for engine mount clearance.

The DLE-20 fits nicely.

I used a DLE-20 template to mark the locations of the new mounting holes. The trick is getting the blind nuts inserted, but with the help of a telescoping magnet pick-up tool it makes the job (barely) more tolerable!

2/26/2011 – Making progress.

Re-routed the throttle pushrod.

No binding with the Sullivan Gold-N-Rod #503 Flexible

Needed to cut an access channel for the throttle push rod in the battery tray.

Installed Sullivan Ball Link Connector on the throttle arm.

Choke pushrod has to run out the side of the cowl due to the spinner blocking access.

Decided to recover the rudder in yellow to match a full scale version of the Hurry Home Honey P-51.

Econokote Cub Yellow.

3/3/2011 – After checking muffler clearance, and not finding any, I decided to go with a wrap around Pitts style muffler to keep from having make a very noticeable cut-out in the side of the cowl.

JTEC wrap around Pitts style muffler.

I had a conversation with another modeler who had just completed a DLE-20/ TF P-51 conversion and used a JTEC muffler. Initially the muffler JTEC made was a bit too wide to fit within the P-51 cowl but after suggesting to JTEC that they modify one, they did. It’s the compact version of their DLE-20 muffler and it’s now a perfect fit.

TF P-51 with a DLE-20 and JTEC compact wrap around Pitts muffler.

Mine is on order and could take up to two weeks to receive.

3/11/2011 – Still waiting for the muffler from JTEC.

An access hole needs to be opened so you can adjust the carburetor needle valves. Since this P-51 uses a half-cowl, the top of the cowl is sheeted balsa and MonoKote. I needed to figure our something that would allow me to cut a hole yet still protect the opening for being damaged and affording a some-what clean look.

I found a plastic bushing made for such an application and although it’s not the best look, it’ll serve its purpose.

1/2″ i.d. Plastic Snap Bushing

First I transferred the location measurements of the needle valves to the inside of the fuse.

Marked the location of the needle valves – make the cut smaller than needed.

Using a handy X-Acto saw blade I rough cut the hole.

Makes better precision cuts than a blade.

Then from the outside I traced the opening and cut out the covering to keep it from tearing. Then made the finish cut with the saw and inserted the bushing.

Cut away the covering to keep in from tearing when making the final cut.

The bushing will be painted Olive Green.

3/12/2011 – Decided to go with a different pilot than the one provided with the kit. I saw this Slimline Xtreme Legend pilot in Pegasus Hobbies, which turns out to be the company that actually designs and manufactures the Xtreme pilots that Slimline markets.

Slimline Xtreme Legend pilot “Dick”. Modeled after WWII Ace Maj. Richard Bong

WWII Ace Maj. Richard Bong.

Stock pilot.

3/22/2011 – She’s all done but the balancing. I’ll need to add around 6 ozs to the tail as she’s a bit nose heavy. I found that this is typical with this model so the conversion overall only added a small amount of weight.

I’ll get pictures of the finished engine compartment and some of the other conversion details soon.

6/11/2011 – Finally able to spend time finishing up the build. I was able to pare the needed tail weight down to 5.4 ozs and figured out a good location to mount it. I took two strips of lead weighing 2.7 ozs each and cut an access hole in the bottom rear of the fuselage. I’ll epoxy each strip of lead to the inside fuselage wall and use silver MonoKote to cover the cutout, leaving the original inspection hole.

Access cutout for tail weight.

11/18/2011 – Stopped flying for a while. Just getting back into it and the maiden is planned for next year.

3/17/2012 – I was planning for the maiden this weekend, but of course its raining! Hopefully next weekend.


3/24/2012 – Took her our for the maiden this morning. It was very overcast and not the best conditions for flying so I decided I’d just break in the engine. Turns out I melted the fill line and couldn’t have flown anyway.

The DLE 20 started up just fine at the factory settings and was just rich enough without any adjustments to transition from idle to high speed without any hesitation and with a nice burble at mid-range. Seems just right for break in. Ran about half a tank alternating between idle and mid-range, 15 minutes at a time, to heat cycle the cylinder.

When I went to de-fuel I was just pumping air, something was wrong. I flipped her over and saw the melted fill line. It cauterized itself enough to not leak but had a pin hole.

Should be an easy fix to reroute the line. It’s supposed to rain tomorrow but if not I’ll give it the maiden another try.


So close….

3/31/2012 – Well, not much better weather today. Very overcast with about a 400′ ceiling but I was ready for the maiden.

Fill line fix worked good and the DLE20 was running great, so out to the runway to give it a go. As soon as she lifted off I knew I was in big trouble. Tail heavy. I don’t understand it because I was so careful with the balancing I have to assume I used the wrong CG measurement point.

I was just lucky to land in one piece and be able to make some adjustments and try again. I’ll remove a bit of the weight, balance again and hopefully get it right.

It’s like flying with the elevator reversed!

4/3/2012 –  Back on the stand at the factory recommended 143mm CG point, which is the same as what I used the first time. I removed 2 ounces to get a little on the nose heavy side (which I swear was how I had it before!). Total weight added now is 3.4 ounces.  I’ll see how she flies and adjust if needed.


4/29/2012 – Finally got in some good flights.  Still have a bit of a trim issue to work out but the DLE-20 with the 16X8 Xoar prop is a great combination.

7/23/2012 – A few months back while in a hard banked turn low on the back side of a small hill at the end of the runway, I had a momentary glitch as the right wing dipped hard and being so low I had no time to recover. She went in full throttle and really destroyed the front of the plane with some wing damage. I gave the plane to a club member who offered to make the repairs for me and I’m waiting to see how it’s going.

8/11/2012 – The repair is done.  It’s a good job considering what was left of the front of the plane.  I’ll add some pictures when I start to get it ready for a re-maiden.

  1. Knockoffs says:

    Looking Good !!!! My P51 is all done and ready to fly. Just waiting another week or so for the ground to dry up.

    Video will be up soon for my first flite (again) of the Top Flite P47 with the DLE 20cc.
    Weather permitting, it will be tommorow.

  2. Knockoffs says:

    P.S.S. You stole my picture. Do i get any royalties !!! LOL

  3. Majicmanpr says:

    Good looking plane. Thank you for sharing the conversion. I was in the process of installing a DLE 20 on a p51 (Marie) by hanger 9 but it feels way to heavy. Also it feels like you can shake up a martini on it. I decided to pull it out and I was looking for a replacement plane. Can you share more details I love what you are doing with the model. I am interested to see how it turns out. Thanks in advance

    • electricdan says:

      I have not had the shaking problem although I’ve read about others that have. Could be a manufacturing issue or a prop balancing issue.

      I have this engine on an Extra that weighs less than 9lbs and is a really good combination.

      I hope to have the maiden flight in the next few weeks.

      Thanks for the comments.

  4. Anonymous says:

    Well done on the maiden, even being tail heavy! Question: Where did you place the ignition module and your receiver? I hear they should be as far apart as possible. Just fitted my engine. Coming along nicely!

    • electricdan says:

      Thanks for the comment. The next flight should be better.

      You can see the silver ignition in this picture:

      It’s in the fuse up front with the receiver in the middle.

      Good luck with yours.

      • Anonymous says:

        Thanks for that. My thoughts exactly on ignition placement. What paint did you use on the bushing you installed? I have also done this mod but need to paint it now.


      • electricdan says:

        Testers Model Master Enamel, Faded Olive Drab

  5. Wes says:


    What prop nut did you use for the DLE20 and Top Flite spinner? The supplied Top Flite nut is too small for the DLE’s shaft.


    • electricdan says:

      I used this one:


      This is the 8×1.0mm Double Jam Nut Adapter Kit from Tru-Turn.

      FEATURES: Steel construction. The screw is tapped 10-32 for cone screw. Used to mount Tru-Turn aluminum spinners onto the following engines: YS .90, 1.20, 1.40 4-Stroke Engines DLE 20cc gas engine

      INCLUDES: One Adapter Nut One Adapter Jam Nut One Propeller Washer One Aluminum Bushing

      REQUIRES: 1/2″ End Wrench To Tighten Tru Turn Aluminum Spinner

      SPECS: Crankshaft Thread Size: 8 x 1.0mm Spinner Mounting Bolt Thread Size: 10-32 Bushing Size: Inner: 8mm Outer: 3/8″

  6. Wesley says:

    Hi again. Glad you have managed to get some good flights in! Mine is now ready to have cg set. I see in your latest pic you have it set to the manual recommendation of 143mm. How is it handling at that setting? Does the nose drop a lot more when retracts are down?

  7. Wesley says:

    Hey Electricdan, how is all going? Have you managed to sort out the trim issue? I haven’t maidened mine yet but almost there. Have you got down trim dialled in to the elevator at this cg setting?


    • electricdan says:

      Hi Wes,

      Yes the re-balancing sorted out the balance problem. Flies real smooth and high speed low passes are awesome!

      Good luck with your maiden, you’ll enjoy flying this plane.

  8. Robert says:

    Hi electricdan,

    I’ve got a question.. since you own(ed) both the TP P-51 and P-47.. which one would you recommend? Which one do you like best? I’m currently in the process of selecting my first warbird and want a relatively easy to fly and build plane (hence the kit and no scratch build). I cannot seem to choose between the Mustang and the Thunderbolt..


    • electricdan says:

      Hey Robert,

      With out a second thought I’d go with the P-47. Easier to build, fly and land.

      Good luck with whichever one you choose.

  9. Mark says:

    Did you have any cooling issues with the engine in such a small cowl? If so, what mods did you make to the cowl to correct the cooling issue?

    • electricdan says:


      No cooling issues at all. I have plenty of open cowl on the bottom which allows for good air flow coming in from the front.

  10. Anonymous says:

    Thanks Dan!

  11. Luciano says:

    Excellent build! I’m building the same plane with the same engine and have a question:
    I bought the Tru Turn Double Jam kit, but did you used only the washer and the flat nut form the kit? Because the spinner bolt dont fit the jam nut provided in the Tru Turn kit. Then I thought that you used the top flite jam nut to fit the spinner bolt, right? And did you have to cut the sipinner bolt? Because my bolt is too long!

    Thanks for helping, and sorry for the bad english, I’m from Brazil!

  12. justin phillips says:

    Would the newer DLE-20RA with the rear exhaust fit this bird without having to buy the jtec muffler?

  13. RODRIGO MACAYA says:

    Hello…. Good job. Great plane. Congratulations. I would like to make a question. Did you get de C.G. point with the landing gear outside or inside? In the original manual, the picture while the C.G. is obtained, the landing gear is showed outside. On the other hand, in your last picture where you show how you get the C.G, the landing gear is inside. I am using an engine O.S. four strokes 120-surpass w/pump which is a little heavy (35.3 oz) so the difference on the amount of weight on the tail is important when the C.G is obtained depending on the position of the landing gear.

  14. Anonymous says:

    The new DLE 20RA fits perfec. There’s no need to purchase a Pitts muffler

  15. Anonymous says:

    I checked the cg with the retracts in the retracted position.

  16. Anthony says:

    Quick Question: I’m building this same plane/engine combo for months now and am now ready to look at upgrading the retracts. I’m not forking out $450 for a Robart setup. I plan on buying Eflite like yours. Questions is, they have 85 degree & 90 degree options now. Robart lists 85 on their website for this model. In hindsight, do you think one or the other will work better? How did the Eflite 90s fit versus how you think the 85s would have on your model? Thanks!!!

  17. justin phillips says:

    In one picture you have the ignition under the cowl, and then you have it in the fuselage. Which one did you end up keeping?

  18. justin phillips says:

    Also how far do you measure the motor thrust washer from the firewall?

  19. Fastflyby says:

    Went with the DLE 20ra. What is your completed empty weight? I ended up at 11.2lbs with pneumatics.

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