RE: AMD Hawk.
 

Hi Guys

It has flown!
but only once [:'(]
I did not fly it myself, but my friend who is an extra ordinary pilot took the maiden flight on her :)
It flys great. He cruised around on half throttle. He started and landed without using flaps, just to see how it performed, after reading horror stories about those flaps ;)
With the landing he made, it sure doesn`t seem to need them, because it came in nice and slow to a very light and beuatiful touchdown with the nose up.

But, the gear mounting plates are so poorly glued in, that they both have been torn loose to some degree.
When the plane had landed, I did not realise this had happened until I began to refuel it for next flight. I could se some strange bulges on the top skin. When I looked undernieth, I could se that both sides had been torn loose. [:@]

I just could not believe it. The landing was silk smoothe.

Im sory, But I did not take a video of it. You know how it is to mainden your plane.....you get all eager, and just want to see it fly, and forget everything else....so sorry guys :)


BTW, the JJ-1400 runs perfect.
Exept for the starter bendix drive. I have to re-align it, as it makes a terrible nose when spooling up ;)
But it starts and runs great.
I found the reason why it started bad the first time. Aparently the gas and fuel valves need to have the fuel/gas in and out the correct way. But because you cant tell what is in and out, I ofcourse hooked them up backwards :-)

The pressure from the gas canister can force the valve open, if you connect the lines backwards on the valve. Thats what happened to me on the first start. I kept feeding it gas, even though the ECU had shut gas valve.

But, there was another guy at our jet meeting who had bought a JJ direct from China. This one did not run too well. There must be an unbalance in it, because when you put your finger nail on the casing while running, you can feel it vibrating. You cant feel a thing when mine is running. Also, I dont think it had the preload spring installed either. If I spun the turbine up with my finger, it would rotate for ages until it stops......none of my other turbines turn as free like that.

He will probably read this thread, and I hope he chimes in for some more infor on how it is ;)

RE: AMD Hawk.
 

Nice 1. congrats...but what a fool for forgetting the maiden video :) taking her out again asap??

RE: AMD Hawk.
 

heh...

Im going to pull the film off, and install the mounts properly. Then glass the whole thing.

RE: AMD Hawk.
 

i am glad the jj was fine for you :D

RE: AMD Hawk.
 

But it is thirsty!

I did not have the timer going, but it seemed to have a high fuel consumption even when flying at half throttle.......but Ill have to time it before concluding anything.

I wonder how much fuel goes to the bearings......as this would probably be the cause......

RE: AMD Hawk.
 

i work mine out next time i have it out i ask andy about fuel to bearings etc.

RE: AMD Hawk.
 

SJN

Still a very nice result for a maiden flight, up and and back again with a whole Hawk allows for further improvements. I'd guess that when you pull the covering back, the retracts are only glued into the foam without any anti rotational torque ribs parallel to the root. On my old pattern ships the retracts into foam wings could withstand some harsh landings over a prolonged period, the essence of multiple touch and go's both into and down wind. Keep the Hawk fans informed of what you find, I'll get the saw ready for some pro active retract surgery.[:o]

Paul

RE: AMD Hawk.
 

Thanks turn and burn.

Looking at the pics I took when I got the engine, it looks like it has no restrictor......at least not visable ;)


Yes Paul, I am very happy with the result. I had too much elevator. Only needed half of the throw I had given it. I had given the full elevator movement until the LE of the stab touched the fuselage when giving full up. It only needs about half of that movement.

Also.....the plastic inside the canopy shrinks in the sun! :)
I look like a red lobster in my face, so the sun was a bit harsh ;) If you look at the base of the instrument panels, you can se the plastic has ben distorted. Maybe if you glued some wood or glassed it or something, it wont do this.

RE: AMD Hawk.
 

I was lucky, and the elevator neutral point was dead on ;)

Here are some pics of the movement mine has.


First two are neutral
3 and 4 are elevator up
5 is full down.

RE: AMD Hawk.
 

The way it is designed seems to be fine. But there is just too little glue on mine......guess I got a lemon wing.
The top skin has not been glued onto the mounting block on the left wing. My right wing seems fine.

RE: AMD Hawk.
 

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RE: AMD Hawk.
 

Do yourself a favor and do a good job here, or you will probably be doing it again.
Every AMD product I have ever seen, flown, or owned, had the same jokey retract mounts, and you are better off fixing them first thing when you open the box, because they are underdesigned, using low quality materials(like double layers of lite ply!) and poorly assembled. Seems like it's a price you pay for these cheap airplanes...I can live with it! But it's easier to deal with right out of the box than after the plane is built. Retracts through the top of the wing, or tearing out on a nice soft landing is NORMAL, not unusual!

RE: AMD Hawk.
 

Sonnich

In my experience a wire leg with a spring in it (eg. springair) usually works best on smaller models flown from grass. The leg will bend and absorb the landing shock whereas the oleo strut will transmit the shock into the mount and expose any weakness there.

I found this with my 'roo and have not used oleos from grass since. The worst you will usually do is bend the wires which can be starightened in seconds.

Anyway, glad the Hawk flew well and damage is minor.

John

RE: AMD Hawk.
 

Good point, too. I would not have gone with struts and grass.
But either way...look at those mounts...they were doomed...

RE: AMD Hawk.
 

The eurokit struts with the trailing link are perfect. Man....I wish I had taken the video now.....you arnt going to believe how good this landing was. There is no way ANY kind of landing gear would have helped here. :)

The problem here looks like that the top and lower skins have not been glued onto the mounts. Its the foam alone that is taking all the beating.

A quick fix might be gluing some triangle stock on the top skin against the ply mounts, and maybe rinning some CA glue between the lower skin, and the mount.....just be carefull it doesn`t run into the foam though :)

RE: AMD Hawk.
 

Easytiger, I think the desing is fine, but it just cant hold up if there is no glue in there...... They did not spare any glue in the fuselage, but the wing.....[:'(]

RE: AMD Hawk.
 

SJN

It is inside not external like many others, with some spare tubing you can just about blow through the restrictor turning slightly purple as you do;) It really would be useful to identify the actual fuel consumption of the JJ1400 turning at 160K to compare.

RE: AMD Hawk.
 

Oh, I'm sure the landing was fine, I have been there, done that with some of these arfs. Perfect landing, gear messed up anyway.
I think, though, the retract plates look like a double layer of lite ply. They use that because they cannot die-cut thicker plywood, so they double up th 1/8" stuff, and the ply they are actually usuing is usually "lite ply", not "aircraft ply", totally different stuff. If you look at most other more expensive jet kits, you will find the parts are bandsawed and sanded from much heavier material like 1/4" ply, because this stuff just does not hold up. But that's up to you. I would definitely replace the material.
Struts and grass don't mix on this scale, I have found. Wire struts are the way to go. If the plane is MUCH larger, struts are fine, but, basically, you have no fore-and-aft shock absorption with just the oleo struts, and that's what you need, more than up-and-down, when flying off of grass. I don't think the struts versus wire would have made a difference, in this case, nor 1/4" plywood, none of that is any good if the mounts are not glued in in the first place!
But save yourself doing this job AGAIN, and make things nice and strong.
Notice BVM uses a breakaway system called "flex plates" because he recognizes the loads incurred here, and that the worst thing to happen, and the hardest thing to repair, is a torn out gear mount, so they make the acutal mounts incredibly strong, then put in a breakaway point that is easy to replace. It's very, very smart.

RE: AMD Hawk.
 

Sonnich, I just purchased an AMD Hawk myself and I was pretty disappointed to find that the instruction booklet is very sparse, hardly readable and the pages look to be copied so many times that the pictures are hard to make out any detail. Also, my hardware package seems incomplete. The elevator mechanism seems to be missing. I have the 2 aluminum bars that slip into the elevators but they are both bent at different angles. Plus, there is no way to join the 2 bars together, they are just 2 pieces of round bar stock, no joiner!! Also, my aileron servo mounting hatches did not fit the size of the openings. They were too small. Based on what I have seen and taking into account your gear problems, I will not be purchasing an AMD product again in the future anytime soon. There is so much work to do on this ARF it might as well be a kit. This is why I build from scratch and not buy ARF's. Anyways, I wanted to ask you Sonnich if you have a support number or a way of getting parts for this plane. I would like them to give me a completely new hardware package, and since they dont have a sheet of the parts count, I dont even know what I am missing!!! So frustrating!!!!

RE: AMD Hawk.
 

I bought mine here from the UK.
http://www.a1models.fsnet.co.uk/
Maybe David there can help you out.


Im not overly disapointed that my gear mounts have failed. My plan was to glass the wing anyway.
But ofcourse, its a bummer to have it happen.
She will fly again!

RE: AMD Hawk.
 

ET

I agree 100% with everything you have said regarding the wire legs on smaller models, anything up to about 16lbs and they are the answer on grass. All my current models are on this system and I have suffered no gear failures.

I had a very hard bounce on my Jetco last week and the subsequent arrival flattened the wheels up against the underside of the wings and fuselage but the gear mounts were fine. Five minutes work and it was ready to fly again. The same type of landing on my 'Roo meant flying was over for the day due to the 6mm pins in the struts being almost impossible to straighten at the field.

John

RE: AMD Hawk.
 

Some pics from the maiden flight.

RE: AMD Hawk.
 

Ian , try contacting by email at [email protected] Try to be very detailed in your description of the parts you need as they don't have the customer support we are use to. I know what you are saying about the manual, it's a joke. Seeing what Sonnich has gone thru i'm debating tearing out the wing mounts [ landing gear] and doing some pre-emptive work. The hawk is my second airframe and I'm just about done on my JHH A-4 Skyhawk. I'm trying to find a good location for the first flights and have not found any of the local fields acceptable. By the way I have the red,white and blue version of the hawk and it is a very nice scheme. Doug

RE: AMD Hawk.
 

Sonnich,

Did you have the JJ1400 rated down for this bird or did you use all it's thrust?

Any comments on the performance with this relatively 'big' engine for this model? Any problems with the idle thrust and/or overall weight? Reason I ask is I'm tempted to go against the grain and put a 54 sized engine in my new Savex F16.

It sounds like the bigger engine was fine in your 'smallish' plane:D

RE: AMD Hawk.
 

well, I did not fly it myself.....but it was flying at half throttle all the time. I do not think it is over powered with this engine.
It came down nice and slow without flaps, so it doesn`t seem to be overweight.

I have to fly it before I come to any conclusions for you guys :)

And no, de-rating the turbine is not a good idea when flying from a grass field. It needs all the afterburner it can get , to get away from the tormenting grass :)


If you look at the last picture Stig put up, you can already see the left leg has been torn backwards already.....the nose hasn`t even touched down there.