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Howdy from New Mexico!

#1
Greetings to everyone! I am a frustrated beginner from Las Cruces, NM who is having a bad run of luck. I am looking for advice, if you're willing to plow through my tale of woe.

For the past couple of years, I have dabbled in flying. first with a Dynam Hawk Sky I got on the cheap, had 10 or so successful flights, and then picke up a couple Parkzone UMX 'planes along with a used DX6i. With those, I have had pretty good luck. I managed to wear out the motor on two UMX p-51's, both of which were flight worthy and their end-of-life. since then, I have been wanting to further hone my skills, and have toyed with scratchbuilding (full disclosure, I am old enough to have mis-spent my youth building stick-and-tissue 'planes, although could never afford RC gear in the late 70's to early 80's). That's when my luck started to go sour. My most recent failure was an FT Simple Storch, which was built out of Model Plane Foam instead of DTF. I reasoned that the build would have to be modified, as the paper on DTF lends strength. my wing had a full 7-ply central spar cut with a 5-deg. dihedral built in, and carbon tubes inlayed in the foam to reinforce the foam and help stiffen the dihedral. the plane came together well, considering the build was substantially different without the paper. It's maiden flight took place a week ago Saturday, and it didn't end well. I used an EMax CF2822-1200KV with a GWS 9x5 prop, with a 3s-2200 battery. plenty of power, very short roll and it took flight. That's when things went wrong; It wouldn't roll, even though I had carefully set my throws exactly as described. after adding rudder during turns, I managed to get it to come around and brought it down safely. I then verified my throws and that everything was working correctly, and took off again. same problem, this time trying to get it to roll at all caused a vicious twitch that broke the wing spar, despite the CF. needless to say, gravity won and the garbage can got a new, broken friend (after stripping the electronics. besides the broken wing, the fuse suffered extreme crushing damage, the landing gear was totaled and I lost the heart to try any repairs, since, even if successful, I would be left with an un-rollable 'plane. I have had rotten luck with a Bixler 3 (mushed fuse after first flight, afraid to try again although repairs appear to have been successful), a Slow Stik (broken three pairs of landing gear due to extreme over-control difficulties), and am seriously getting frustrated. I was able to do fine with the UMX 'planes, I do well on simulators, and I am really careful about setups, CG issues, etc. I feel like I am missing something, and am unwilling to turn to the local club flyers as they have been very closed and impolite about advice. Any thoughts? I am starting to wonder if I should find a new way to spend time and money...
 
#2
Addendum to previous post

I should also clarify what advice I am looking for: is there a good choice for transitioning from micro park flyers to larger planes? I am open to suggestions, and really welcome any thoughts any of you have...
 

Gazoo

Active member
#3
Apprentice S 15e

My first plane was the Apprentice S 15e. It has the SAFE technology with the "panic" switch. I spent about $250 on it but learned a lot. I estimate that if I went with another plane without the SAFE that I would have spent much more than $250 in parts/repairs.

It is super stable and easy to fly in beginner mode. Get the plane up "two or three mistakes high", as they say, and then put to expert mode. If it gets out of hand, flip back to beginner mode or hit the panic button and it will save the plane instantly. As a note, the panic button does not keep the plane from being viciously grabbed out of the air by trees.

I then built (and crashed) many of the 3-channel planes like the Speedster, Old fogey, Nutball, Flyer and Delta. They were all fun to "fly" (by fly, I mean crash) but if I were to do something different, it would have been to transition directly to the Storch. The Storch is roughly the same size as the Apprentice and pretty docile. I could have just skipped over the 3-channel and went directly to 4-channel. I believe that it it better to start right away with a stable 4-channel than to try to transition from 3 to 4.

A word of warning about the Apprentice though. You said that you have a DX6i. There is considerable effort getting the DX6i to work with the SAFE function. I was using a DX5e which comes with the RTF Apprentice.

If I understand correctly, you were attempting to "roll" the Storch? Like a barrel roll or just banking to turn?

I would definitely try the Storch build with DTFB. As the weight of the foam board changes, the CG will be different. Control issues will follow. I can't tell you exactly why this is though. Maybe someone else can explain.

I hope you keep on trying. It's pretty cool when you start coming back with the same amount of pieces that you left with...
 
#4
Storch problems

I was just trying to roll about 15-20 degrees to turn the silly bugger. I may be crazy, but I wouldn't barrel-roll a maiden flight at my skill level. it really wallowed and fought rolling at all, and there was only about a 3 mph wind. the CG was spot-on according the the build instructions: once I could get it to turn (at all), it would hold straight and level pretty well. I was up about 50-60 feet, which bought me enough time to get it sort of lined up for a downwind landing once I realized that things were working incorrectly. I have looked at the Apprentice on a couple of occasions; I like the high wing, and it is well-reviewed as being durable...
 

Gazoo

Active member
#5
Hmm... I have built the storch (and smashed to bits) three times. I don't know how much dihedral to use. I think that there is a gauge on the plans. It seems like 5° is quite a bit. Could this be the turning/banking issue? Anyone?

The weak spot on the Apprentice is the vertical stabilizer. They have a tendency to part ways with the airframe. This, as you know, is not good. I check it before every flight.
 

Hai-Lee

Old and Bold RC PILOT
Mentor
#6
Welcome to the forums!

It sounds like you fell into a seldom mentioned feature of large foam wings and that is span-wise torsion, (twisting), when ailerons are used. At high speed this can lead to control reversal, (NASTY). I suspect that your elaborate plywood wing spar failed in flight because the twisting of the wing and the spar caused it to delaminate and just fall apart at the point of failure. Plywood spars do not like being twisted.

During the heyday of foamcore wings larger planes used Balsa sheeting over the wing to provide rigidity and to stop the twisting of the wing as well as plywood spars.

You do not state if you are now able to access foamboard but if you do then build another Storch or similar. If you do not you could build again using modellers foam in the same manner as you did previously but this time sheet the wing with either thin balsa or even heavy paper.

The only other suggestion would be to dial in a heap of EXPO into your controls because the aerodynamic forces on large planes are greater than on small planes and their mass is higher so a rapid change in control input, (Stick Banging), can put severe forces into the wing and tail surfaces. Expo will reduce the tendency for you to over-control the model in flight.

Simulators do not use planes with wing flex, torsion, CG problems, incidence errors, Thrust line errors, and a myriad of other design and build issues. Experience is the best teacher, and after your failed build you are now more experienced so I encourage you to try again.

Finally I will state the 3 basic rules to a successful model flight.

1. Preflight
2. PREFLIGHT!
3. #@$#%@$ PREFLIGHT!!!!!

Just as a cheap suggestion try one of the trainer designs, (fly well, medium size, cheap, adaptable). The Tiny trainer is a very cheap design with a moderate wingspan and following that try the Das Ugly Stick both fly well, not too fast, and cheap to build.

Have fun, (ALWAYS).:black_eyed:
 
#7
further clarification

The wing spar I made was seven plys of Model Plane foam, as plywood would have likely exceeded the weight of the rest of the plane. basically a 2-inch wide 1/2 inch solid slab of foam. the 5-degree dihedral was based entirely on the spacer provided, and was within 1/8 of an inch of the spacer (by being a tad more flat). In any case, I may try another Storch, but with DTF and not right away. I am still a little sore about the way this went down (literally).
 

Hai-Lee

Old and Bold RC PILOT
Mentor
#8
The twist of the wing with a laminated foam spar would have been far worse. From your description you would have been lucky to fly it at all. Also as mentioned above by GAZOO the dihedral could be a hindrance to rolling efforts. The storch already has considerable "Pendulum" stability and so it could easily do without any dihedral at all.

With a little redesign work you could make a three piece wing without a dihedral or wing joint over the fuselage. the two wing tip joints would have far lower forces trying to pull them apart than the original central wing joint.

Just a little note, the Storch which "Died" should not be viewed as any sort of failure but rather as a challenge. You should not be discouraged if your build failed because we all have a closet full of planes that just did not make it. You should rather think of yourself as an EXPERT in training.

The day may come where I need an answer to a problem which you have encountered and overcome. Do not be put off now because I am sure I will be desperate for that answer!!!:eek: