Crash Analysis - Great Planes Decathlon 40
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- Опубликовано: 18 сен 2024
- RC Jim examines the flight data, comparing it second by second with what we see in the video to work out what happened in the crash of this beautiful plane. He then examines the wreckage to see what we need to do to fix it - and we will!
Def looks like an accelerated stall, that turn was pretty sharp. I did something similar with a Hangar 9 Spitfire… hate to see a balsa model go down.
Yes, a model like that does go "crunch"
I'm not an expert, but I have crashed my share of Decathlons. You haven't addressed the elephant in the room...Decathlon models are super prone to tip stalls if you turn too deeply while having the throttle way too low. What I saw in the video was a plane that wasn't responding well to aileron or rudder input and tip stalled on that last turn which caused it to fall out of the sky. One concern I was curious about was did you move that heavy servo outbound on the wing when you went for a shorter aileron? If so, that is gonna contribute to sluggish aileron response as the angular momentum is increased. If it was designed that way, then never mind on that count. Ask your field buddies why they think Decathlons fly bad. Looks like from the beginning, you never really had much throttle after initially cutting back. I felt your pain on that maiden and am sorry for your loss. Best of luck on the rebuild and make gentle turns under power when setting up for landing. I understand that most of the flight was not usual flying and know you are a competent pilot. If things like this never happen, then maiden flights would not be a little tense.
Thanks for the input. One of our really good pattern flyers at the club also thinks that it stalled near the end. Around that time I was in a state of mild panic, and wasn't thinking about the throttle. With most of my planes the descent to the field keeps enough airspeed going, so I can cut the throttle until I begin to level out near the end of the field. If I had better control earlier on, then I wouldn't have gotten either the plane or my mind in that sort of state!
Re. the aileron servos, they are HiTec HS225BB servos. Smaller and lighter than standard servos but very quick and powerful. They were not the problem.
Dispiace vedere un crash di un modello , ma confido nella tua caparbietà di ripararlo e di portarlo in volo. È la dote piu importante per un aereo modellista, buon lavoro
grazie per il tuo incoraggiamento e supporto
Jim, Another possibility could have been the covering coming loose.
this can cause a ton of drag on one wing and at least contributed to the crash.
Model airplanes need washout to make them more stable. I have a old model plane book from the 70s that describes this subject.
Carnage 😢
Great analysis 👍
I think your over thinking this a little. You're not flying fast enough
to make such small amount of aerodynamic difference with that little peace you intend to add, just
add more to the throws to your control surfaces and add some expo .
You should be golden. 😊
Thanks for the tips. Hopefully it will be great with increased control throws.
so did you recover and analyze the cockpit voice recorder (orange box) ?
:-) Of course, I do have my great commentary on the video!
I built a great planes Decathlon, and crashed on landing, I got to slow and it stalled and spun in to the left. Dey jaa veu, you have to fly them fast , and use power on landing