Dle-55. Top Flite Mustang. Overheating, 22-10 prop
10-13-2013, 06:49 AM
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Dle-55. Top Flite Mustang. Overheating, 22-10 prop
I have a Top Flite Mustang With a Dle-55. The engine head sticks out under the cowl. Plenty cooling. Running 32/1 Stihl Ultra. Have a Xoar warbird prop 22-10. After about 8 min. of flight at almost middle to WOT passes. The engine will bogg down a little and miss slightly. With a 22-8 I didn`t have that problem. But I like it with more pitch because it seems to land better and is faster. RPM at 6600 on the ground. Spec`s show it should run with this prop. Engine has about 25 flights on it. Just went to the 22-10. Flew 6 flghts so far. On my last flight if I didn`t push it hard and stayed half throttle it did better. Start very easy. Thanks. You can go to my Gallery under Valve Floater to see Pictures.
Last edited by Valve floater; 10-13-2013 at 06:59 AM.
10-13-2013, 04:47 PM
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No. Do I rich`in it? On the ground it has good RPM. I can`t get it to over heat on the ground. Turning 6600 on a 22-10 prop should be with`in spec`s?Not sure. Thanks
10-13-2013, 08:48 PM
#4
10-14-2013, 05:43 AM
#5
Like is mentioned above, my experience with these engines is that they are a 22 X 8 engine. So on a war plane, you need to run a 20 or 21 X 10 to get the fast fly-by speed.
Listen for signs of engine sag up in the air like when you are turning to start your fast fly-by.
Listen for signs of engine sag up in the air like when you are turning to start your fast fly-by.
10-14-2013, 10:38 AM
#6
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While not in a Mustang, I've run a 22-10 before w/o any problems. It was a mismatch for the airplane so I switched to a 23-8 but the engine had no problems pulling the 10 pitch. In my opinion, a 22-8 is a bit small for a DLE55 and it really turns up with that prop.
My guess is you have a cooling problem in the mustang. Just because the head he hanging out in the breeze there is no guarantee the engine will cool. Its all about how much air flows through the cooling fins, not past them. Another source of problems in tight cowls is carb heating. Those rear carbs packed well back in the cowl can vapor lock to varying degrees leading to a lean condition. If you have a wrap around Pitts muffler under the carb the problem can be even worse as it really restricts airflow around the engine and moves a heat source closer to the carb. Again the solution is to get some fresh air into the area which can be difficult in a Mustang while trying to maintain the scale profile.
Some photos of your cowl arrangement would be helpful.
My guess is you have a cooling problem in the mustang. Just because the head he hanging out in the breeze there is no guarantee the engine will cool. Its all about how much air flows through the cooling fins, not past them. Another source of problems in tight cowls is carb heating. Those rear carbs packed well back in the cowl can vapor lock to varying degrees leading to a lean condition. If you have a wrap around Pitts muffler under the carb the problem can be even worse as it really restricts airflow around the engine and moves a heat source closer to the carb. Again the solution is to get some fresh air into the area which can be difficult in a Mustang while trying to maintain the scale profile.
Some photos of your cowl arrangement would be helpful.
Last edited by Truckracer; 10-14-2013 at 10:41 AM.
10-14-2013, 03:40 PM
#7
While I agree that some pictures would help us narrow down some possible causes I think the high speed just needs to be opened up a tad. The OP stated that he had no overheating issues with a smaller prop and did not re adjust after changing props. Start with simple stuff first.
10-15-2013, 07:59 PM
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Thanks all. I tried to load some pictures but the file was too big. Please go to my gallery here. Under valve floater. I have some there. Trying to figure out where to order a 21-10 prop. Not very common. If I open the high needle will that help with cooling or RPM with the 22-10 prop? I have side, not wrap around muffler. If The plane runs great the first WOT passes. Then it will start to sagg down and miss slightly. On my last run I didn`t push it that hard and it did better. I have a 22-8 warbird prop I had on it before and it did ok. I did notice with the 10 pitch it landed a lot better. Or it might be my imagination?
10-16-2013, 08:59 AM
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+1 on simple stuff first.
I've been running DLE 55's on 23x8 for 3 years now, I always retune for a prop change or fuel change or oil type change or any other change that might effect the tune.
Richen that up a tad, it will not cost you anything.
My 23x8's run well over 7000rpm.
I've been running DLE 55's on 23x8 for 3 years now, I always retune for a prop change or fuel change or oil type change or any other change that might effect the tune.
Richen that up a tad, it will not cost you anything.
My 23x8's run well over 7000rpm.
10-17-2013, 07:11 PM
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It`s sounds and runs great on the ground. If leave the 22-10 prop and rich`in the H jet what am I looking to hear and see? RPM is now at 6600. Will I be looking for and increase in RPM`s? Thanks
10-18-2013, 08:01 AM
#13
My Feedback: (19)
I had viewed the photos in the gallery but noted no photos of the cooling exits. Views of the cowl bottom and rear would be helpful. Other than that the suggestions of richening the HS a bit are right on but no amount of richening will compensate for poor cooling.
10-18-2013, 01:11 PM
#14
This is worth note. A P-40 has a huge air outlet at the back of the cowl. Hard to tell in the pictures but the P-51 pictured appears to not have any provisions for air exit. As Truckracer stated, it wont matter where the H needle is if the hot air can't get out.
10-18-2013, 04:57 PM
#18
10-18-2013, 07:19 PM
#19
My Feedback: (19)
[QUOTE [Drop a prop length 21-10 and up the RPM, engine will perform better at 7500 to 8500 RPM. /QUOTE]
If we were talking about a G62 here I'd agree 100% as it would be perfectly happy turning those higher RPMs but I'm not quite so sure about a DLE55 doing the same. The G62 has a well supported, dual counterweight crank where the DLE (and similar engines) has a single counterweight cantilever crank. My bet is the crank pin or bottom end rod bearing will eventually give up one the DLE or even on a DA for that matter. A 22-10 is anything but a heavy load for a DLE55 and mine turns that prop or a 23-8 within 100 RPM of each other. For aerobatics I prefer the 23-8 for better upline pull and braking on downlines but if I had that engine in something like a Mustang or other warbird, I'd have a 22-10 on it.
If we were talking about a G62 here I'd agree 100% as it would be perfectly happy turning those higher RPMs but I'm not quite so sure about a DLE55 doing the same. The G62 has a well supported, dual counterweight crank where the DLE (and similar engines) has a single counterweight cantilever crank. My bet is the crank pin or bottom end rod bearing will eventually give up one the DLE or even on a DA for that matter. A 22-10 is anything but a heavy load for a DLE55 and mine turns that prop or a 23-8 within 100 RPM of each other. For aerobatics I prefer the 23-8 for better upline pull and braking on downlines but if I had that engine in something like a Mustang or other warbird, I'd have a 22-10 on it.
Last edited by Truckracer; 10-18-2013 at 07:22 PM. Reason: Quoted wrong post.
10-18-2013, 08:13 PM
#20
Hi guys, I have been running a 23x12 narrow and it really pulls the mustang nice. when I put the 22x8 back on it she turned into a real pig and that was the last time I flew it with a 22x8. I also have a good sized hole behind the engine for exhaust air outlet, it goes from the front of the engine to the firewall. I have not had any heating problems.
10-19-2013, 05:03 AM
#22
After the flight you may want to pull and read the plug. If it's white you're lean. Also, if the air can get into the cowl but not out that will contribute to the problem as well. In my experience the DLE 55 should turn a 22X10 around 7000. I've seen them turn a Xoar 22X8 at 7700 with the Jtec muffler.
10-19-2013, 06:37 AM
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When the engine overheats, measure the temp when you bring it back down. If the head temp is approaching 200 degrees F you have a cooling issue.
Nice & simple.
10-19-2013, 07:10 AM
#25
The first thing would be to richen the mixture. It is alao the easiest. A bigger prop requires more horsepower and horsepower requires fuel. Simple. I would always run an engine as rich as possible without sacrificing performance. To lean an engine to get 200 rpm is just a sign of going to lean.
If no change then I would probably look at air flow across the engine. But if it is simply over propped then nothing will fix it.
Try different props. Just because the numbers are smaller doesn't mean the speed will be less. I have had a 15x8 Vess outrun a 15x10 APC. The same goes for a 18x6 Vess vs a 18x6 Xoar. Props are not created equal.
If no change then I would probably look at air flow across the engine. But if it is simply over propped then nothing will fix it.
Try different props. Just because the numbers are smaller doesn't mean the speed will be less. I have had a 15x8 Vess outrun a 15x10 APC. The same goes for a 18x6 Vess vs a 18x6 Xoar. Props are not created equal.