I turned my pipe upside down from what Skymaster says. Also I see you removed plywood from the top on the pipe support, that was a mistake. Remove plywood only from the bottom until the pipe fits, this will give the pipe enough of a downward angle. I angled the exhaust nozzles in a more scale downward angle. I would forget about the afterburner rings if they are in the way. Not a single burn mark on the tail.

Hi

I flipped the skymaster pipe upside down, but grinded the upper part of the formers. With the turbine at 6º down, it flew wonderfull today

For those who remember, I toasted my stab a year ago. Now it is covered in flitemetal with rivets and so on and there is NO ABSOLUTE SIGN of heat in the stab

Cg at 330mm

Happy man today

Regards

Nuno

BLUF: how do you service the air/oil nose strut?

I'm assuming you input a volume of x weight car shock oil, cap it and then add air pressure

Ive been able to deduce its 40psi but I don't know the volume or weight of the oil.

I asked a buddy today today but he said "fill the oil to the top". That doesn't do it in that it creates a hydrolock (unless I'm using too heavy an oil"

thanks in advance

Dave

The instructions are on Skymaster's website; Skymaster Air

I was advised by BVM to use Automatic Transmission Fluid (ATF), so that's what I did.

Joe,

thank you. I knew I saw it somewhere but couldn't find it

Two errors on my part:
1. Using high viscosity shock oil. The ATF worked great!

2. I filled the strut full on the extended position and then capped it. The right answer is bleed it, compress it, then cap it.

I think the book says 37-52 psi. That seemed high for the nose strut. That must be a measurement for the mains

thanjs again
Dave

SM F4 Balooning on take off
 

Hi everyone,
Recently fixed up a few issues (landing gear plates, etc) with my SM F4 (Stock SM pipe) with KT 210 which seems to have excellent power and plane flies great. Replaced my old batteries in the nose as well going with Li 3800 v.s two 4800 before. I didn't see any reason to double check the CG after the changes. I have marked the plane at 300-310 previously. Here are the two issues i noticed:
1) Plane starts ballooning after take off without any elevator input if take off role angle is little higher than 25 degrees or so (only if you take off at very low angle (10-15 deg) it won't balloon. i immediately banked to take the high angle or gave it major push elevator to level if off otherwise it would pitch to full vertical. Checked my take off flaps and were around 33mm TE from CL.
2) i am also noticing pitch coupling on full throttle in cruise mode. (which i am thinking of adding some throttle to elevator mix, I can mix any profile with 28X)

As i mentioned at this point I could not be sure if my CG is off and by how much but it flies and lands very easy. no odd behavior other than what was noted.

Any feedback is greatly appreciated.
Jason

The jet will pitch up at low speeds at full throttle settings with the stock SM tailpipe....not sure if this is what you are describing. I actually hold a little down elevator on take-off roll until it reaches take-off speed, otherwise it will take-off by itself. My igyro helps at 40%gain (with 10% hold) in pitch for better behavior on take-off. Also, I dropped the aft end of the pipe lower at the rear mount for even better behavior. My F-4 does not change pitch trim in flight. CG at about 315mm. Make sure as well you have down thrust on your engine...should be approx 5 degrees down. Hope this helps.

Here's a video of mine from Thurderthrust in Sep 17.


Cheers,
Cheers,

You should flip the stock pipe upside down. I did it and the throtle elevator issue almist went away. Be sureyour turbine is 6—8° with downthrust

cg should be no less than 330mm

regards

Nuno