aehaas

FYI, yes the airfoil is as you say it should be. It is the only way you can install the elevators. I thought it was odd but having seen you show this and it being the only way they fit into place I went with that arrangement.

I have 3 levels of throw for my surfaces. I always maiden with the middle settings so I can give it more or less as needed. The ailerons are about right in the middle setting but the elevator was too much. I took the lower setting and moved it to my middle position for the next flight and took off some expo. It was 20 and now 15. I have 0 expo when pushing the elevator. For some reason I fly best inverted with no expo and in some cases negative expo when pushing the elevators.

AEHaas

aehaas

I was reviewing the video. You can always pick up some things when doing so. For one I noticed the air sock was showing a 15 MPH cross wind when I was coming in for the landing. After I touched down I needed to give it full right rudder to stay on the pavement:

tp777fo

My Feedback: (28)

Oh the dreaded flap slap failure. Immediate pitch up to a stall at pattern altitude. Handgrips -raise, triggers - squeeze

scoeroo

My Feedback: (9)

Nice one Ali , good maiden , plane still in one piece - was a good day
Yes as you say Ali - still some minor trimming to be sorted , seemed to be a touch pitch sensitive

aehaas

I got the correct paint and sprayed up the scoops. They are now mounted to the plane:






I am planning on a second flight tomorrow.

AEHaas

aehaas

'Back from the second flight. Much more subdued today. 'Sorry, nobody there to take a video. I am getting close on trim and throws. No bouncing around. I tried a knife edge and was holding at 120 MPH but had some coupling, will work that out at another time. The plane tends to slow down more than other jets while into turns I noticed. I generally give more throttle in every turn when I fly jets. Especially if I was only doing "average" speeds on straight-aways.

I tried the gyro again and did not have any oscillations on the high setting but was not going top speed either. For now the Spectrum AR3000 gyro is set at around 25% for normal flight and 40% when the gear is down and the flaps are set to landing position. All flight surfaces have the same percentage settings.

Next is to do some loops and cubans.

I had 1.3L of fuel left after a 5 1/2 minute flight. I upped the timer to 6 minutes to see where I end up next.

AEHaas

jetspud

Good to hear the successful flight reports

David

kevinthoele

My Feedback: (1)

I ended up installing rubber band on the tiny nose door and it comes up with the gear

aehaas

I ended up using a servo that was 50% stronger for the small nose door and made sure I had 100% mechanical advantage with the door fully open. It worked fine on the second flight yesterday.

There was a mishap however. After I landed and shut it down there was a gust of wind that blew the horizontals stabs down hard. One got stuck vertically somehow. I could not easily straighten it so I turned the receiver on. There was a grinding noise and still the stab would not move. I had to open it up and free it but the servo was stripped. I do have an extra servo. I am into the repair now. I am planning on adding some blocks to prevent over rotation of the stabilizers from this point further. Take Note - this is a must.

Smart people learn from their mistakes (most of them anyway).
Really smart people learn from the mistakes of Others!

AEHaas

aehaas

I installed the rubber baby buggy bumpers on the down elevator side. I used sticky rubber feet on square balsa posts. But I also glued them in place around the edges. When the epoxy dries enough I will do the bumpers on the other side. The overall motion is still more than twice the "high rates" setting. When the servos are energized obviously there is no need for these motion limiters.

When there is no power to the servos however the elevators can passively move past 90 degrees and get stuck. This happened with just a gust of wind the other day. Also, when stuck down the elevators almost touch the ground making it hard to wheel the plane back to the benches.





AEHaas

sysiek

My Feedback: (176)

jetspud

aehaas

OK, I think after three flights it is about dialed in. The only thing that is lacking is enough braking power. The ones supplied are discs with a sand-paper like surface. I need to see if these can be optimized or maybe I need something else. Another option is to use more pressure but then I need to have an air tank and I am trying to avoid anything that extends the set-up time and aircraft weight.

AEHaas

scoeroo

My Feedback: (9)

Curiosity - what are your final trim settings ?

aehaas

'Been thinking of how to answer this. It depends on a lot of things per aircraft. I can say that the elevator is giving me a little up elevator at level flight with flaps up. It is not directly even/level/in line to the wing angle. This goes along with the fact that the plane is a bit nose heavy fully fueled. There is probably less up elevator as I was able to move some of the weight of the fuel back over the CG whereas this model normally has all the fuel forwards of the CG.

The elevators are positioned with a little bit of down elevator with take-off flaps. And a little more down elevator with full landing flaps at 45 degrees down. It is just a few mm difference, not as much as the plans would suggest.

AEHaas

aehaas

I am out of the loop for a few weeks more but I will get back to the plane soon. In the meantime there are some developments on the JetCat P-130 turbine. I did not mention previously that it seemed to have more power than advertised and it sucked up more fuel than advertised. This may all be true as one reads this thread:

http://www.rcuniverse.com/forum/rc-j...l#post12518314

AEHaas

sysiek

My Feedback: (176)

aehaas

‘Nice work on your plane. It’s amazing how much work these planes are especially if you want to do a “little” customization.

For my T-38 I wanted to make braking stronger and long lasting. I changed to pneumatic Intairco wheels and brake hubs from Dreamworks. I had to add an air tank. It is a medium sized one as it only works the brakes. So far I filled it once, played with it in the shop, flew once and it is still essentially full of air. Also it has sat around for over a month. Obviously it uses about no air and there are no leaks. I had to use a U-aluminum channel inside the hub as the Skymaster struts are narrower than the Intairco slot on the hub. So a little fitting was needed. No big deal but the braking is now what it is supposed to be. This plane does come in, land, a little fast so it is important to have good braking as my field is only 500 feet long. If you are short at all or even long you will have your gear ripped out, it’s very unforgiving.

I have been busy with a lot of other things so further progress and test flying will be a little scarce for the time being.




AEHaas

aehaas

I got around to flying recently and took out the NASA T-38. I performed some loops, split-s and cubans. No issues. The only thing to keep in mind is that the model slows more than other jets while in turns so give it more throttle while turning. I got too slow once and almost got into trouble. It does take some getting used to. This is not a beginners airplane.

The JetCat P-130 is an excellent match, plenty of power in my plane.

AEHaas

sysiek

My Feedback: (176)

frankmokaya

Hi guys,

I'm new to the forum but have been reading along as I build my skymaster T-38. I just finished the build and find that with the tanks full (UAT full, gear down, take-off configuration), I am a bit nose heavy and with the tanks about 1/4 full (UAT full, gear down, landing configuration) I am a tad tail heavy.

I can adjust my flight packs and get it so that in the landing configuration the plane sits level. However I will be even more nose heavy when taking off.
BTW, I am using a C.G of 108mm from the leading edge of the wing where the outboard portion of the wing meets the front portion of the wing that attaches to the fuse. I read the detailed posts about that on this post. Thank you guys!

My question is should I worry about being level when landing or is a little tail heaviness ok? I should also add that I am using AR smoothflight (gyro) on this plane an that wet (takeoff configuration the all up weight is about 17.4kg).

Thanks,

Frank

kevinthoele

My Feedback: (1)

Frank

I have tons of flights on my T38. It came as a kit so it may even have been the first one Skymaster sent out years ago. Show me a pick of the cg measuring location. It should be 108 back from the seam where the wing joins not the fuse!!!!. I balanced mine there no fuel gear down and It flys great. I do not have trim changes during flight

kevinthoele

My Feedback: (1)

Frank you can give me a call to discuss if you like

281-615-8455

frankmokaya

Hi Kevin,

I have pics but RCU will not let me post (apparently until I have 10 posts). But yes. I am at 108mm back from the leading edge at the break in the wing (not where the wing meets the fuse!

frankmokaya

Sincere thanks to kevinthoele for taking the time to talk me through the setup and initial prep of this jet. She flew super well and even though I pulled out the gear one a subsequent flight, the T38 is a pleasure to fly. Looking forward to flying this more. Video of the flight on my YouTube channel, FlyWithFrank.

Frank