Top Flite '.60 size' P-51D Mustang ARF: Building & Modifications
#3101
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Join Date: May 2010
Location: Lakeview, OR
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Ok!! I got a couple flights today with the DLE mustang now that it is trimmed out and balanced correctly it is a great flier clocked it at 80mph with the radar gun using a 16x8 I think once the DLE is finished breaking in and maybe a 15x10 prop it should see 90mph? Its a great flier!
#3103
Join Date: Jan 2010
Location: , UNITED KINGDOM
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#3104
Join Date: Jan 2010
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OK I have my retract setup at last. Robart 635 left and right robostruts and eflite electric retracts
I need to replace the stock electric retract legs with the robart robostruts and the one thing i noticed is that the diameter of the robarts is wider than the hole in which they would fit into the eflites. The diameter of the robarts is 9.5mm and the diameter of the eflite legs is 5mm. Do robart do these struts in a narrower diameter and if not how do I fit these robarts into the eflites. I am aware that the screw comes out to drop the original struts out of the electric motors but once these come out will the 9.5mm diameter robart struts fit into the holes of the electric motors?
I need to replace the stock electric retract legs with the robart robostruts and the one thing i noticed is that the diameter of the robarts is wider than the hole in which they would fit into the eflites. The diameter of the robarts is 9.5mm and the diameter of the eflite legs is 5mm. Do robart do these struts in a narrower diameter and if not how do I fit these robarts into the eflites. I am aware that the screw comes out to drop the original struts out of the electric motors but once these come out will the 9.5mm diameter robart struts fit into the holes of the electric motors?
Last edited by autotecart; 04-10-2015 at 01:01 PM.
#3106
My Feedback: (17)
My eflite's didn't have the wire adapter. What I did was to take the wire that came with the eflite and cut a 1" piece off of it, took the smaller of the two inserts that came with the robo struts. Drilled it out to 5mm and put the robostrut on the 1" wire. Worked perfectly.
They must have changed the design of the eflite retracts to accept the 9.5mm robostrut. Good idea and good to know since I'm about to order a set for my Mustang.
They must have changed the design of the eflite retracts to accept the 9.5mm robostrut. Good idea and good to know since I'm about to order a set for my Mustang.
#3109
Well I'm all but done now. I'll post a few pictures. I just need to instal the optical kill switch and an batt on/off switch. I have a Jtec pitts style wrap around muffler that looks great. Although that muffler doesnt have a pressure nipple for the vent line, so ive done the old ventline around the fuel tank twice and out the bottom of the plane.
But I'm having second thoughts about the combo of a 155cc engine and the 14x8 four blade prop. The engine specs state that the engine performs best with a 2 blade 14x6. So a 4 blade 14x8 may be way too much for it! Thoughts? It will fly but performance may be lacking and I really hate that. So for the maiden it will be with an APC 14x6 two blader.
I may need to swap out the 15cc for a 20cc that I have NIB, but at the moment that is just too much work to contemplate. And I was going to drop the 20cc in the new Hangar9 Corsair which arrives in Australia in June.
The finished product does look good and I'm satisfied that the retracts have a solid base now, lots of ply and 30 minute epoxy.
Looking forward to the maiden although there will be a deal of trepidation, not the least because this 15cc engine's last flight ended in a fatal deadstck shortly after take-off when it was in a Seafury. I just cleared the field was in the process of gaining height over dense bush and then nothing.....smash! So I'll be resetting all the needle valves and giving it a lot of testing before taking the Mustang into the bright blue yonder!
Wish me luck.
But I'm having second thoughts about the combo of a 155cc engine and the 14x8 four blade prop. The engine specs state that the engine performs best with a 2 blade 14x6. So a 4 blade 14x8 may be way too much for it! Thoughts? It will fly but performance may be lacking and I really hate that. So for the maiden it will be with an APC 14x6 two blader.
I may need to swap out the 15cc for a 20cc that I have NIB, but at the moment that is just too much work to contemplate. And I was going to drop the 20cc in the new Hangar9 Corsair which arrives in Australia in June.
The finished product does look good and I'm satisfied that the retracts have a solid base now, lots of ply and 30 minute epoxy.
Looking forward to the maiden although there will be a deal of trepidation, not the least because this 15cc engine's last flight ended in a fatal deadstck shortly after take-off when it was in a Seafury. I just cleared the field was in the process of gaining height over dense bush and then nothing.....smash! So I'll be resetting all the needle valves and giving it a lot of testing before taking the Mustang into the bright blue yonder!
Wish me luck.
#3111
A gas engine doesn't need muffler pressure and if you had it hooked up like that before that may have been your problem. A 15cc engine does not have the power to swing a 4 blade prop, you will be way under powered. Stay with a 2 blade and save the 4 for display.
#3112
My Feedback: (3)
I'm flying the stock ARF with a DLE20 side exhaust and APC 16X8. Radar gun pass at 108mph, repeated the pass three times to check.
The previous owner combined battery packs into one larger 2600mah pack for use on both the ignition and Rc. I'm not a fan of this set up but its lighter I guess. Two to three flights don't draw more than 700mah.
Anybody flying with Down Trim?
This model requires quite a bit of down trim which is tricky on the ground as it wants to pitch the nose down. I have to hold up to neutralize the elevator and gain speed until the stab is flying then relax to neutral stick in the air.
Incidence issue I'm sure but I have not looked into it much further at this point.
The previous owner combined battery packs into one larger 2600mah pack for use on both the ignition and Rc. I'm not a fan of this set up but its lighter I guess. Two to three flights don't draw more than 700mah.
Anybody flying with Down Trim?
This model requires quite a bit of down trim which is tricky on the ground as it wants to pitch the nose down. I have to hold up to neutralize the elevator and gain speed until the stab is flying then relax to neutral stick in the air.
Incidence issue I'm sure but I have not looked into it much further at this point.
#3114
Senior Member
My Feedback: (26)
IMO you have a CG issue. The plane should be balanced at 27% MAC and trimmed at 3/4 throttle setting. I posted my flight review on the forum if that helps.
I'm flying the stock ARF with a DLE20 side exhaust and APC 16X8. Radar gun pass at 108mph, repeated the pass three times to check.
The previous owner combined battery packs into one larger 2600mah pack for use on both the ignition and Rc. I'm not a fan of this set up but its lighter I guess. Two to three flights don't draw more than 700mah.
Anybody flying with Down Trim?
This model requires quite a bit of down trim which is tricky on the ground as it wants to pitch the nose down. I have to hold up to neutralize the elevator and gain speed until the stab is flying then relax to neutral stick in the air.
Incidence issue I'm sure but I have not looked into it much further at this point.
The previous owner combined battery packs into one larger 2600mah pack for use on both the ignition and Rc. I'm not a fan of this set up but its lighter I guess. Two to three flights don't draw more than 700mah.
Anybody flying with Down Trim?
This model requires quite a bit of down trim which is tricky on the ground as it wants to pitch the nose down. I have to hold up to neutralize the elevator and gain speed until the stab is flying then relax to neutral stick in the air.
Incidence issue I'm sure but I have not looked into it much further at this point.
#3115
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Join Date: Dec 2001
Location: Litchfield Park,
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The old style Evolution 10, 15, and 20cc gas engines do require muffler pressure, the only gas engines I've seen designed that way. I don't think it was a particularly successful design idea evidenced by the fact that all of the aforementioned engines have been updated and re-released with pumped carbs.
#3116
My Feedback: (3)
If the CG was tail heavy this plane wouldn't fly like it does especially on final. I can make very small inputs and it tracks nicely. I've done stall tests with zero, half and full flaps and it checks out just fine.
If it was tail heavy it would be unforgiving as it slowed down and to date I've see no evidence of this behavior. In addition I've yanked and banked it around chasing a fast foamy with no problem or departure in flight at speed.
No evidence of any CG issue that I can tell. That's why I suspect an incidence problem with this particular model. I didn't build it so I'm not sure yet. It's my buddies plane I fly it with him.
If it was tail heavy it would be unforgiving as it slowed down and to date I've see no evidence of this behavior. In addition I've yanked and banked it around chasing a fast foamy with no problem or departure in flight at speed.
No evidence of any CG issue that I can tell. That's why I suspect an incidence problem with this particular model. I didn't build it so I'm not sure yet. It's my buddies plane I fly it with him.
#3117
Anybody flying with Down Trim?
This model requires quite a bit of down trim which is tricky on the ground as it wants to pitch the nose down. I have to hold up to neutralize the elevator and gain speed until the stab is flying then relax to neutral stick in the air.
Incidence issue I'm sure but I have not looked into it much further at this point.
#3118
My Feedback: (3)
Ok, interesting, yours balanced ok though?
Just a thought but what engine and prop did you use?
I have marks on the wing next to the fuse I'll have to measure from the LE and compare to the book.
I'm yanking and banking at high speed and its stable so the CG must be right. I have seen even the Giant Scale snap out of a turn so I have been watching closely for that tendency.
When I roll it inverted I do have to hold some down to maintain altitude, thinking back on this weekends flight...
Anyway, its a crowd pleaser and knife edge passes at 10ft and 100mph get the old guys in the peanut gallery talking... lol
Just a thought but what engine and prop did you use?
I have marks on the wing next to the fuse I'll have to measure from the LE and compare to the book.
I'm yanking and banking at high speed and its stable so the CG must be right. I have seen even the Giant Scale snap out of a turn so I have been watching closely for that tendency.
When I roll it inverted I do have to hold some down to maintain altitude, thinking back on this weekends flight...
Anyway, its a crowd pleaser and knife edge passes at 10ft and 100mph get the old guys in the peanut gallery talking... lol
Last edited by Chris Nicastro; 04-20-2015 at 07:14 PM.
#3120
The old style Evolution 10, 15, and 20cc gas engines do require muffler pressure, the only gas engines I've seen designed that way. I don't think it was a particularly successful design idea evidenced by the fact that all of the aforementioned engines have been updated and re-released with pumped carbs.
So now I'm using the same engine (so no pressurised carb) and I have a vent line just going out of the plane with only atmospheric pressure. Will that be OK? I'm inclined to dump this engine and drop my OS 20cc gasser in it with the 4 blade prop.
Thoughts?
#3121
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Join Date: Dec 2001
Location: Meridian, ID
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I've had two TF P-51's. They both had a touch of permanent down trim even with a rear CG. They fly just fine and I never bothered trying to correct any incidence issues. With the retracts angled forward 3 deg, I have no nose-over tendencies.
#3122
It was a wet weekend so no chance to maiden the shiny new plane, and just as well.
I thought I'd better test out the engine some more before attempting flight and it became immediately apparent that under load the engine would fail instantly. This was because (despite what the HH reps advised me) this engine (Evolution 15cc) does need muffler pressure. The vent line to the atmosphere is not sufficient. So I took the presure nipple off my stock muffler and tapped a new hole in the Pitts style wrap around muffler, reworked the vent line to that and bingo! All Good. Previously as soon as I held the plane striaght up at near full throttle the engine died. Now it was good.
I'm away next weekend so the maiden will have to wait until the following weekend.
I thought I'd better test out the engine some more before attempting flight and it became immediately apparent that under load the engine would fail instantly. This was because (despite what the HH reps advised me) this engine (Evolution 15cc) does need muffler pressure. The vent line to the atmosphere is not sufficient. So I took the presure nipple off my stock muffler and tapped a new hole in the Pitts style wrap around muffler, reworked the vent line to that and bingo! All Good. Previously as soon as I held the plane striaght up at near full throttle the engine died. Now it was good.
I'm away next weekend so the maiden will have to wait until the following weekend.
#3123
My Feedback: (3)
It was a wet weekend so no chance to maiden the shiny new plane, and just as well.
I thought I'd better test out the engine some more before attempting flight and it became immediately apparent that under load the engine would fail instantly. This was because (despite what the HH reps advised me) this engine (Evolution 15cc) does need muffler pressure. The vent line to the atmosphere is not sufficient. So I took the presure nipple off my stock muffler and tapped a new hole in the Pitts style wrap around muffler, reworked the vent line to that and bingo! All Good. Previously as soon as I held the plane striaght up at near full throttle the engine died. Now it was good.
I'm away next weekend so the maiden will have to wait until the following weekend.
I thought I'd better test out the engine some more before attempting flight and it became immediately apparent that under load the engine would fail instantly. This was because (despite what the HH reps advised me) this engine (Evolution 15cc) does need muffler pressure. The vent line to the atmosphere is not sufficient. So I took the presure nipple off my stock muffler and tapped a new hole in the Pitts style wrap around muffler, reworked the vent line to that and bingo! All Good. Previously as soon as I held the plane striaght up at near full throttle the engine died. Now it was good.
I'm away next weekend so the maiden will have to wait until the following weekend.
Best of luck on the eventual maiden. I suggest getting to know her up high and do slow flight and stall tests to understand how slow you can land. We have a 500ft runway with a fence at each end so my approach is as low as I dare over the fence and I still use most of the runway to settle it down and roll out. I do use flaps as needed for wind conditions. Its a great plane with no real bad characteristics like many Mustangs have.
#3124
I agree, not many bad flying characteristics. Mine has a DLE 20 and Robart Air Up Spring down retracts. Almost 300 flights on this plane. Six years old an doing great so far. At 11 lbs takeoffs and landings are not bad for a warbird. Plan on landing on the mains, it get too slow with flaps to try to three point. Solid in the air, goes just where you point it, almost like a pattern plane.