Thread Tools
Jun 25, 2021, 10:01 PM
Registered User
Thread OP
Discussion

F22 Crash - any ideas?


This was the second flight of my F22 where I wanted to do GPS speed test.
Almost as soon as she got to max throttle she rolled right and I'm not good enough yet to save it.
It is a twin 70mm and I confirmed the engines would sustain max throttle for a period of time after the crash.
I did have the starboard elevator servo making noise even with no load on the servo but have never seen it deflect the elevator on its own.
I did have a different receiver AR8630T in her with SAFE off just AS3X gyro on (might have had a better outcome with SAFE on).

Anyone have any ideas as I don't like to crash but to not learn why is even more frustrating.
Thanks
Mike

LX F22 Twin - Flt#2 Crash (2 min 18 sec)
Sign up now
to remove ads between posts
Jul 13, 2021, 06:18 AM
Registered User
kcmj's Avatar

f22 crash


Hi Mike
The video shows both elevon's at full deflection when control is lost resulting in a high speed stall. Angle of attack was too high relative to the forward airflow.
Stalls don't just happen at low speed. They happen at high speed too. A stall is all about angle of attack in relation to the relative airflow over the wing. The wing will stop producing lift at this critical angle. Can I suggest looking up some reference books relating to Basic Aeronautical Knowledge used as study books for Private Pilots Licences. If you study aeronautics it will save you a lot of money in model planes. A classic example is why you should use rudder to level the wings at low speed instead of the ailerons.

Hope this helps Mike.

Keith
Jul 13, 2021, 06:21 AM
Registered User
kcmj's Avatar
Check out my F22 Crash. Mine was a servo failure as I did not use strong enough servos.
<https://www.youtube.com/watch?v=ZkiFgkpSdy4&ab_channel=staples919>

Keith
Jul 13, 2021, 06:35 AM
Registered User
kcmj's Avatar

F22 Crash


Try this link. I struggled to keep control of this plane until the elevon servos finally gave in. It was a full composite model with twin 70mm fans.

Pro design F22 Maiden and crash, My fault (2 min 55 sec)


Keith
Jul 28, 2021, 04:37 PM
Proud To be A Circle Flier....
PaulB's Avatar
Mike,

so a twin 70mm DF F22 must weigh at least 1 1/2 Kg ('bout 3 pounds) and probably does 80 - 160 km/h ('bout 60 - 100 mph).

I just see one video of a modeller flying responsibly at what looks like a club field somewhere well away for anything or anyone that/ who could get damaged/ hurt.

Then I see a video of a Guy flying from what looks like a public access car park (maybe a park) and flies the model directly towards and then (I would bet) over a busy road.

The 'pilot' then turns to overfly (or be very close to) a residential area.

Then does it again before crashing at full throttle.

All this with a model which has previously had problems with a servo and the pilot (by his own admission) is not very competent ("I may have inadvertently, errantly put in right aileron").

Can't (don't want to) help with why you crashed but I can help with the advice that if you think that flying an (at least) 1.5 Kg twin DF at (at least) 80 Kph over innocent bystanders with a model of that nature (actually, with any model) is OK our hobby would be better off without you.

Probably not what you want to hear and I am sure that you will make a lot of indignant noise telling me how safe and responsible you really are but I can only comment on what I can see. It's unfortunate but I hope that this puts you off the hobby because if (when) you cause a serious 'incident', us responsible modelers will suffer. Maybe all of your models will be short lived and you will move on before anything serious occurs.

Not going to apologise, even if this sounds harsh, because I have seen the danger that irresponsible 'people' (not going to say modellers) are becoming to 'my' hobby, a hobby that I have loved for over 30 years and am now at risk of loosing, sadly, due to people doing things like what you do in your video.

Paul
Latest blog entry: Just To Say Hello.......
Jul 28, 2021, 05:22 PM
Registered User
AntiArf's Avatar
Wouldn't the Billionaire Space Club shooting up heavy objects in space be ahead of the risks placed on the public, versus the average modeler flying a foamy jet? Can we get the FAA registration card to do that?

Maybe a servo issue. The gyro is constantly making the servos respond as fast necessary to maintain direction, where the servo continues to travel until the gyro is satisfied with the correction. You would probably never observe it, but just a light side gust would cause a rapid correcting response, where the servo would normally return to center as soon as the correction was no longer needed. Now say a servo failed right when it was at it's maximum throw necessary to make a correction. The servo could easily be far enough from center to cause a sharp banking turn.

RTFs are heavy and not forgiving. Gotta be on top of them to fly them, and have good gear. Personally I lost interest in the heavier foam jobs when I started building light weight balsa EDFs. You can get away with a lot more, as weight reduces. The servo loads are greatly reduced also. I use 5gm tops on the larger jobs, normally 4g and under, and haven't had any failures. Built and flew a GWS262 with tiny 12mm BL inrunners and EDF50 fans. The weight reduction made it completely different from flying with the stock setup, which doesn't have the servoless retract weight which most of the newer foam jobs it's size and larger have. I'll call it a trainer with the weight reduction, with stalls now at the speed one would expect from a light weight trainer. https://www.rcgroups.com/forums/show...&postcount=413

I flew a 22" delta at 9oz where the first flight had a number of uneventful vertical stalls not caught on the video, and was challenging to keep track of. Trying to trim the full flying stab and fly a responsive model at the same time can be interesting. At the light weight the vertical stalls were no issue, simply dropping the nose and going again. First time it happened I thought oh no, but it was nothing, due to the low AUW. It's the first model I ever used a gyro stabilizer on, which made it almost Piper Cub easy to fly IMO. With the gyro stabilization, I would have had to make a pretty bad pilot error to have something like the first crash video happen. https://www.rcgroups.com/forums/show...nd-video/page3
Last edited by AntiArf; Jul 31, 2021 at 05:06 PM.
Sep 08, 2021, 07:39 PM
Registered User

Speed kills.


In almost anything. Never exceed your abilities. No drugs, alcohol or doctor ordered drugs. . My B P medications are bad for faster model control.
Sep 17, 2021, 09:54 AM
This bird you cant change.
FMS DUDE's Avatar
Man what a bad crash, ouch!
Sep 19, 2021, 06:26 AM
Paper Plane Scratch Builder
Lufo's Avatar
Quote:
Originally Posted by PaulB
Mike,

so a twin 70mm DF F22 must weigh at least 1 1/2 Kg ('bout 3 pounds) and probably does 80 - 160 km/h ('bout 60 - 100 mph).

I just see one video of a modeller flying responsibly at what looks like a club field somewhere well away for anything or anyone that/ who could get damaged/ hurt.

Then I see a video of a Guy flying from what looks like a public access car park (maybe a park) and flies the model directly towards and then (I would bet) over a busy road.

The 'pilot' then turns to overfly (or be very close to) a residential area.

Then does it again before crashing at full throttle.

All this with a model which has previously had problems with a servo and the pilot (by his own admission) is not very competent ("I may have inadvertently, errantly put in right aileron").

Can't (don't want to) help with why you crashed but I can help with the advice that if you think that flying an (at least) 1.5 Kg twin DF at (at least) 80 Kph over innocent bystanders with a model of that nature (actually, with any model) is OK our hobby would be better off without you.

Probably not what you want to hear and I am sure that you will make a lot of indignant noise telling me how safe and responsible you really are but I can only comment on what I can see. It's unfortunate but I hope that this puts you off the hobby because if (when) you cause a serious 'incident', us responsible modelers will suffer. Maybe all of your models will be short lived and you will move on before anything serious occurs.

Not going to apologise, even if this sounds harsh, because I have seen the danger that irresponsible 'people' (not going to say modellers) are becoming to 'my' hobby, a hobby that I have loved for over 30 years and am now at risk of loosing, sadly, due to people doing things like what you do in your video.

Paul
Why did you even bother to post? None of it is helpful.
Sep 19, 2021, 06:36 AM
Paper Plane Scratch Builder
Lufo's Avatar
Quote:
Originally Posted by msidler
This was the second flight of my F22 where I wanted to do GPS speed test.
Almost as soon as she got to max throttle she rolled right and I'm not good enough yet to save it.
It is a twin 70mm and I confirmed the engines would sustain max throttle for a period of time after the crash.
I did have the starboard elevator servo making noise even with no load on the servo but have never seen it deflect the elevator on its own.
I did have a different receiver AR8630T in her with SAFE off just AS3X gyro on (might have had a better outcome with SAFE on).

Anyone have any ideas as I don't like to crash but to not learn why is even more frustrating.
Thanks
Mike
A strong chance you will never find out what caused this. The right servo making noise is no guarantee the servo is bad. Many servos chatter
once powered up. What you don't want is to look at a powered up servo and watch it hunt for the center position. At best, you can use your
transmitter to exercise the servo and see how it performs, check the wiring harness leads for poor connection. This plane has thrust vectoring
so that may be an issue as well.
Sep 19, 2021, 08:44 PM
Registered User
alibongo's Avatar
I found this thread because I was looking up "unexplained loss of control". I'm just learning with ailerons, flying low speed, turned, and it just fell, with no control (no damage, it's just a prop parkflyer foamie). But everything was working when I picked it up.
I suspect I stalled it- too slow airspeed, too steep a turn, too close to the ground.
Later I'll practise the same manoever but closer to me and higher up and see if I stall.
Sep 19, 2021, 10:04 PM
Paper Plane Scratch Builder
Lufo's Avatar
Quote:
Originally Posted by alibongo
I found this thread because I was looking up "unexplained loss of control". I'm just learning with ailerons, flying low speed, turned, and it just fell, with no control (no damage, it's just a prop parkflyer foamie). But everything was working when I picked it up.
I suspect I stalled it- too slow airspeed, too steep a turn, too close to the ground.
Later I'll practise the same manoever but closer to me and higher up and see if I stall.
Flying slow and using ailerons will induce a stall pretty quick or at least hurry up a stall that is pending.

Try using rudder when on slow approaches or flying slow and low. I have done a lot of slow and low to the ground when using flaps on my
HH Valiant and doing tight manoevers close ( 18 inches to 24 inches ) to the ground and using ailerons. The flaps adds some stability but even then, there is a line one does not want to cross.
Sep 20, 2021, 08:16 PM
Registered User
hook57's Avatar
“Flying slow and using ailerons will induce a stall pretty quick or at least hurry up a stall that is pending”
LOL, that is a good one! So you must land really fast (not slow) in order to use ailerons or else the plane will stall!! Keep the the flight controls coordinated and all is good!! :0)
Sep 25, 2021, 09:08 AM
This bird you cant change.
FMS DUDE's Avatar
Made in china?
Sep 27, 2021, 10:01 AM
Proud To be A Circle Flier....
PaulB's Avatar
Quote:
Originally Posted by Lufo
Why did you even bother to post? None of it is helpful.
Well that's your opinion Fella and you are certainly entitled to it. Luckily the vast majority of modelers here will have the understanding, depth of knowledge and experience to see a dangerous situation when they see one and will not condone such behaviour.

Paul
Latest blog entry: Just To Say Hello.......


Quick Reply
Message:

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Help! Strange problem after a crash - does anyone have any ideas? mactac FPV Talk 5 Sep 17, 2021 09:56 AM
Help! QAV-R crash. Any ideas? Viper82 Mini Multirotor Drones 0 Feb 05, 2017 06:17 PM
Discussion New Plane crash-Any ideas please? mustangsforme Xtreme Power Systems 35 Dec 26, 2008 07:03 PM
Discussion Crashed F86 sabre. any ideas for the fan? hallstudio Electric Ducted Fan Jet Talk 1 Sep 20, 2006 11:23 AM
Pilatus Porter crashed, any idea? RookieOne Beginner Training Area (Aircraft-Electric) 6 Dec 18, 2001 04:04 PM