RC Groups

RC Groups
    Foamy EDFs
        Question Alfa Model Ta-183 Huckebein problems

#1 moocowfish Apr 10, 2010 10:55 PM

Alfa Model Ta-183 Huckebein problems
 
Hi
I have just got back from maidening my huck, and i had alot of problems, when it is launched it seems to pitch up no matter how much down elevator i have and it quickly loops over and bang!! straight into the ground. Has anyone else had a simular problem?
I have triple checked the CofG and its a little nose heavy to be safe. I have put a brushless in as the motor so there is heaps of power, maybe too much? Is that possible?
Also i checked the throws, same as the instructions say, even that bit of up aileron they suggest.

Im starting to think it didnt have enough air speed, but ive looked at the videos on the web and i think i was doing the same, maybe not. Some videos even show it taking of, of the ground !

Well now my Huck has some glue holding broken bits together and a bit of tape, much like most of the Foamies at my club i see.

I really would appreciate any input from anyone who thinks they can help.

thanks very much
Rob

#2 Jagzilla Apr 11, 2010 05:33 AM

Sorry to hear your Huck is already got the tape on it, that sucks on a new plane for sure. I have only seen one of these out at our club, and to be honest it flew like a typical Alfa jet. In other words fairly easy to handlaunch and a pretty good all around flier.
If as you say, the cog is correct...plane balanced upside down with battery in it, and the elevator is set up correctly, then it must be in the launching technique.

Handlaunch into the wind directly(very important with edf's). A level, or slightly upwards firm , but powerful toss. Let plane build up a bit of speed before starting to pull back on elevator, or give any aileron input. This is how I launch my edf's, and if they have enough power they just basically fly out of my hand. I don't think power is the issue with yours, and you can never have too much power in an edf. From what you describe it does sound like a cog issue to me, or perhaps elevator throw/setup, so perhaps some experimenting with that might be in order. One thing that I do with my edf's is what I call the "hover test". I just stand and hold the plane with the tail down, and give it full throttle. If while holding it lightly, I can tell it is putting out enough thrust that it is trying to hover(while I'm holding it), I know I've got enough power for a good, strong jet. If the plane just sinks down to the ground, then I know it's not going to be fun to handlaunch at all. You might want to try this with your jet, and just see where you stand for power.

Maybe there is an answer here for you, and hopefully others will give you some more thoughts or suggestions.


Best of luck with it, Alfa's are generally nice planes to fly, so I hope you get your's sorted out without too much more grief.
Jag

#3 CaseySP Apr 11, 2010 07:57 AM

Hi Moocowfish,

I lost my Alfa MiG15, veteran of 90 odd flights, to its first hand launch. Prior to that I had always ROG'd it. Then one day, when the field was too dewy for a ROG stupid here decided to hand launch. It did pretty much what you described, but 90 previous flights proved it was perfectly trimmed, CoG correct and throws were all correct.

Many Alfa MiG15's have been lost this way, and I think this is a problem with mid-wing EDFs - the CG is quite high as the battery pack etc is all mounted above the ducting. They may actually need to be thrown at or just below the horizon.

My suggestion is to ROG it if you have access to a good field with smooth, shortish grass (hard to find here at the moment I know with the drought and water restrictions). With my replacement Alfa MiG21 I have installed a bungee hook.

#4 moocowfish Apr 11, 2010 06:52 PM

Hi
Thanks Jagzilla and CaseySP, your ideas are very encouraging, i think the ROG is a good idea, ill have to give that a go !
Also Jagzilla, i read you said get the COG upside down, i did mine with the plane up the right way, maybe thats the problem when i get home ill try it upside down, do you think that will make a difference? I still put my fingures on the wings though, even though the COG marks are on the fuse? Is that correct?
thanks again. ill let you all know how i go !
Rob

#5 clinth01 Apr 12, 2010 06:04 PM

Just a thought - is the incidence of the horizontal stab set correctly? That would cause pitching up, no matter how much elevator throw that you have.

#6 moocowfish Apr 12, 2010 06:08 PM

Hi Clinth01
Good thought, im not sure how to measure this or actually waht it should be, ive read the building instructions over and over and it is quite vage on how and exactly how to place the Horizontal stab, so i glued it with common sense, what i thought looked right.
If you have any ideas on how to check it, or actually what it should be, id appreciate it.
thanks
Rob

#7 riechsoldier1 Apr 12, 2010 10:34 PM

i went to maiden my alfa huck last week, after looking at it on the shelf for 2 years. i bought from a member here who had built but never flew it so i tried first to rise of ground with it but both times it slid on the grass and flew into the air and flipped and landed on its back breaking in different areas. so i taped it up and threw it this time and it flew very fast expoding into the ground. happened in an instant,the alfas are very fragile and hard to repair they crack easily even if you hold it to tight.look great but not durable,i wont buy again, 150.00 for a 5mm foam hollow molded airframe smashed in seconds. the other threads about this huck talk about same thing, people loosing them on the first launch, nose flips up and they break 4 feet from the ground, my other jets would survive that easily. i guess i shouldve kept it on the shelf, now its in the trash can at the park,good luck with yours, im curious what they cost in checholslovokia were there maid, maybe hobby lobby is jacking up the price

#8 Slaanesh Jun 29, 2010 12:37 AM

Hello moocowfish.

Just wondering what happened with your Ta-183? Did you find out anything in regards to the COG or the angle of incidence on the tailplane/elevator assembly?

One thing I've read in the instructions is that you should perform a test glide (no power!) over long grass. It should glide reasonably well if well trimmed.

I've only just received my Ta-183 so I am going to start building it soon.

#9 moocowfish Jun 29, 2010 12:49 AM

Hi Slaanesh
I did fix up the TA and tried hanging the incidence of the tail. Then i went to a park i know where there is a 20 foot high grass slope, so i went to the top and did the glide test, actually throwing the TA slightly down instead of straight. It glided, not exactly like my gliders but it definately glided and i had control. So i went back up the hill and powered to about 3/4 and did the same threw it slightly downwards (which i could do because i was up the hill) and it went well. It seemed once up to a decent speed i gained control and it flew quite nicely.
My conclusion was that i was throwing it straight or slightly up like i do my other hand launch planes and it just couldnt get enough speed up with the EDF quickly, hence it going out of control and stalling etc.
hope this helps and i hope you have more luck than i did.
regards
Rob

#10 Slaanesh Jun 29, 2010 11:12 PM

What motor do you have in your Ta-183?

I'm going to replace the speed 300 brushed with an MP Jet 25-25/26.

#11 moocowfish Jun 29, 2010 11:20 PM

Hi Slaanesh
I used a Turnigy 2615 EDF Outrunner 4800kv for 55/64mm from hobbycity, seems to have a tonne of power for such a small motor. I did have to buy an adapter for the shaft from someone else though.
Rob

#12 topforce Jun 30, 2010 11:32 AM

I had an alfa ta183 a couple years ago. It used stock hobby lobby brushless setup which was mpjet ac 25/25 4100kv motor, and old thunder power 1320 3slipo. It flew great on that setup. every hand launch got my heart racing due to marginal power. After getting up on step though, it flew great.

I lost it against a grey cloudbank. When I found it again it was nosediving about 10 feet from the ground. Was the most beautiful mushroom cloud of depron I ever saw. Only things salvaged were motor and esc,, thats it.

#13 Slaanesh Jul 01, 2010 12:44 AM

Quote:

Originally Posted by moocowfish (Post 15434494)
Hi Slaanesh
I used a Turnigy 2615 EDF Outrunner 4800kv for 55/64mm from hobbycity, seems to have a tonne of power for such a small motor.

I checked the specs on this at HK. Wow. Sounds almost overpowered.

Quote:

Originally Posted by topforce (Post 15437537)
It used stock hobby lobby brushless setup which was mpjet ac 25/25 4100kv motor, and old thunder power 1320 3slipo. It flew great on that setup. every hand launch got my heart racing due to marginal power. After getting up on step though, it flew great.

I would imagine the stock brushed is even worse as it max RPM is quite a bit lower than the MP Jet 25-25/26. I wonder how many people flow this with the original stock brushed speed 300?

Anyway, I plan to make it at light as possible with the lightest RC gear, etc. Hopefully this should help a bit.

#14 BadLemon Jul 01, 2010 12:23 PM

To all

I just maiden my Ta-183 last night at my local field. I first flew my new alfa typhoon 3 times to work up to the Ta-183. Then as the sun was starting to drop I decided it was time. A few weeks back I did the glide test and everything went well but right after that the winds picked from 5-7 MPH to 15 and above so I did go with the power flight. I decided I was going with the ROG "from what I have read was the safest" applied power went to about 3/4 and it pickup speed very quickly. Then I applied back pressure and she lifted off and broke ground. I continued with back pressure and applied a little more power about 2 feet off the ground. Then she accelerated and pitched up into a vertical climb! Before I could respond she was 30 plus feet in the air! "My buddy that was supposed to be video taping this said WOW I wish I got that on tape! I wanted to beat him with a stick." I then quickly reduced power and level he out. She kept wanting to climb so I trim several clicks on down elevator till she flew level. I also had to trim right aileron. After that I how sensitive she was to aileron input so I made slow wide turns for the rest of the flight. At this point I was in the air for about 5 minutes so I decided to slow her down and see how slow she could fly. I almost couldn't hear the engine when I said that is slow enough. I then made a couple of circuits around the field to plan for a landing. I remembered from the manual that she likes to glide and boy are they right! It took 3 attempts to land her and when she did land I had to walk to the other side of the field to retrieve her. So the first flight is in the books I'm very happy about that but I have some work to do with the setup not much but I want to put some expo in the ailerons and double check CG. I feel that the power setup is on the high side but that is not bad but boy dies she want to fly fast! My next flight will be this weekend I plan on some video this time. It's my fault I should of asked my buddy if he has his cam going but I forgot with the maiden jitters going. Here is the power setup I have in the Ta-183

5 blade alfa fan E-flite park 400 4200k inrunner motor produces 16oz of thrust @ 17 amps and a e-flite 20 amp speed controller powered buy a thunder power 11.1v 2100mah 20c battery.

#15 moocowfish Jul 01, 2010 05:40 PM

Hi BadLemon (love the name)
Great description of the maiden, pity about the video, oh well, if you can get a video next time that would be great.
I have tried a rise of ground and its interesting to hear how yours went straight up, mine did the same, the only difference was that i couldnt level out, no matter how much down elevator i put in it stayed pointing at the sky, because it has alot of power it stayed flying vertical for a while untill the inevitable happened and i crashed. I since have repaired it and moved the incidence and COG and i think it flys better now.
I look forward to your next report and hopefully a video !!
regards
Rob


All times are GMT -5. The time now is 05:27 PM.