Look what happened today!

[Biggles' Elder Brother - Moderator]

Good news on the job front Phil - its not all bad eh! Congrats!

 

Someone who actually saw the crash and could feel the wind conditions at the time is more likely to be right than us all squinting at a tiny image on a video!

 

BEB

[Myron Beaumont]

It would appear that most of us agree that a stall was the cause.

[Gemma Jane]

As BEB says standing on the field at the time is very different to watching a vid. Makes me wonder though as I always thought a reasonable nose down attitude with a model would be enough to be safe, has been so far for me, seems the conditions on the day might have caught a lot of people out?

 

[Tim Mackey]

Posted by Big Phil on 28/06/2010 21:02:25:

Spoke to one of the more experienced pilot's today  who saw the crash , and he said , in his opinion, defiantly a stall. As I turned up wind my air speed was greatly reduced just prior to it dropping away.

 Bought bits and bobs today to start the rebuild , planing to spend the day on it tomorrow , then some wally spoils it by offering me a job, after 6 months out of work , starting tomorrow - how inconsiderate.   

  Only joking , really glad to get back into work    

    B.P 

 

Chuffed for ya on the job front Phil

The model damage doesnt look too bad...soon have her back in the air mate .

Edited By Tim Mackey - Administrator on 28/06/2010 23:09:20

[Biggles' Elder Brother - Moderator]

I agree Gemma Jane - in my experience keeping the nose down, and so the airspeed up, works for me. But you can always get the odd freak wind conditions, local sink, turbulence etc. all designed to blow our little theories out of the water - or in this case out of the air!

 

If flying was easy and held no "surprises" we'd all get bored real fast!

 

BEB

[David Ashby - Moderator]

 then some wally spoils it by offering me a job, after 6 months out of work , starting tomorrow - how inconsiderate.   

  Only joking , really glad to get back into work    

    B.P 

 

 

Great news Phil  

[ken anderson.]

go on phil-well done...enjoy new job=££££££££....yabba dabba doo....

 

   ken anderon...ne .1...

[Former Member]

[This posting has been removed]

[Gemma Jane]

Well watching it again I guess the only advice is to keep the bank angle really shallow in the turns to avoid a stall if it dead sticks again Phil or as said just turn as needed into wind and land straight ahead. Making me wonder if a Wot4 would be a better bet for me for my first go at IC.

[Andy Gates]

I am sorry to see the crash of your model but I am not quite convinced by the stall theory  from watching the video.

Watching the earlier flying of this model in the video, I would suggest that maybe the model was overcontrolled which caused the spining out issue.

 

Regardless of the cause of the spin out, the real issue as you have stated yourself is the lack of fuel in the plane.

 

However this should not really be an issue either since we are all taught to land deadstick.

Maybe a little practice in deadstick approaches may be some help to avert this happening again.

When you do practice, try planning the approach and using small control movements to reduce speed and height loss which is so critical in situations like these.

 

Appologies if I am "teaching grandma to suck eggs" but I have seen too many losses due to poor control and planning in a deadstick situation, normally caused by panic.

 

 

[kc]

Gemma

You wont regret getting a Wot4 because they have no nasty vices. 

Useful for testing a wide range of engines too.

Building your own is best and if you ask around at your club you are very likely to find someone who has the plan ( originally it was a plan before the kits )

[Phil May]

Hi Andy,

I have, like us all, had a few dead sticks in the past with no problem. This is my first low winger ( my other models include Panic Bipe and Big Stik ) and , to be honest, the slower speed glide characteristics compared to my other models caught me with my pants down . (no appologies needed, I am always prepared to listen )

 At the end of the day, it was my fault, simple as that . 

 Made a start on the repairs, i'll post a few pics when I upload them.

 

        B.P 

 

 

Edited By Big Phil on 29/06/2010 20:28:42

[Andy Gates]

Good luck with the repairs Phil.

It takes a very honest man to admit it was his fault, so congratulations on that score.

 

I guess I am lucky in that I come from an RC thermal gliding background where you only get one chance to land in the right place so deadsticks are of no concern to me.

 

Almost all my power planes have stall tests done on the maiden flight and simulated deadsticks on the second so I know how they are going to handle if I have a power out.

 

I taught one flyer to fly after a poor reception at a local club.

He did get bored with all the practice I made him do but it has stood him in good stead.

However a deadstick on the maiden of his pride and joy (flown by me) just after take off proved to him the use of the practice.

 

The plane, a nice big 1.20cuin 4 stroke powered Cessna, had taken off and just cleared some trees on climb out when the motor went dead.

His first reaction was that it was a dead loss and we were going to be picking up pieces.

I had other ideas, levelled off from the climb and carefully turned the plane around.

A shallow dive dropped the plane below the level of the tips of the trees but gave valuable speed which I used to hop over the tops.

Once over, the nose was dropped to maintain speed and a carefull approach allowed the plane to be landed safely about 5 yards from where it started.

 

The expression on his face was priceless.

The plane went on to fly many more missions.

There are lots of things that should not be done in that story but practice will pay off as you can "feel" how the plane handles which is really necessary in emergency situations.

 

Looking at the previous machines you have listed as having flown, the difference between them and the PC9 are quite marked.

The effect of the taper of the wings is going to be more noticable on the flight charecteristics than the low wing design. This would not have helped at slow speeds especially if you use largish aileron movements.

The thinner wings will make the plane less floaty too, giving a much higher stall speed than you are used to.

 

I guess I am saying get your machine fixed and then go and enjoy practicing with it so you can get her back next time - although I hope there is no next time.

[Peter Beeney]

Big Phil,

I’ve seen this phenomenon a few times, and the first time we really tried to crack it was many years ago. I was watching a friend, a pilot that was flying on his own, but with not a great deal of experience. He was practising rectangular circuits and landing approaches, with a model Chipmunk, some 50 - 60 ins span. At the time he was doing left hand circuits, he was going down wind, from right to left, much too slowly as I thought at the time. As he banked left on to the base leg the model started to bank to the the left and then instantly flicked over to the right. “There you are” he said “Interference. Right in that spot. I’ve had this before, just there.” Fortunately the model was quite forgiving because, probably due to the fact that he’d not violently banged the sticks about, conveniently froze, I guess, the model recovered sufficiently for him to be able to open the throttle and fly out. I managed to persuade him to climb to height and fly round again where it very obligingly did the same trick again. At that point I also managed to convince him that it wasn’t interference. The site was an airfield, the landing strip was the peri-track. It was generally breezy there, and also open to gusts. Talking our way round the circuit, we decided that when the model was going down wind the wind was thus striking the back of the model, the air speed over the wing was at it’s lowest point and so the lift from the wing would be at a minimum; if the model was going very slowly it was only perhaps barely lifting the model. Just as he turned left I think it’s possible that a gust struck the up going aileron from behind and thus tended to force the left wing up again, the opposite being true for the right wing. This explanation seemed to fit the circumstances, because when he flew faster, in a shallow dive, with a few more revs on, right round to the final approach when he could then close the throttle, there was not the faintest a sign of even a twitch.
I suspect that when I’ve watched full size aircraft manoeuvring at airfields it is for maybe this sort reason that something like a Pitts, with four aileron, always seem to zoom round at high speed, only throttling back right at the last moment, just as the wheels are touching the ground.

I’m not sure this is any sort of a correct explanation, but it certainly seemed to work for us. PB

[Martin Harris - Moderator]

Posted by Eric Bray on 29/06/2010 11:29:28:
One of my homebrew models does that. If I stall it while banked, it reverses roll, no matter which direction it was banked in, and applying more aileron causes a reverse ail response! I concluded that the down-doing ail was fully stalling the wing, thus over-riding the effect of the up-going ail on t'other wing.Luckily, when i discovered this, i was high above the ground, and on top of a hill, so although it got the adrenaline circulating, i had enough time to realise that, even though it had gone nose-down in a near vertical dive, it was rotating the wrong way!  When i let the ails off, the rotation stopped, and then normal flight resumed. Ail differential was introduced at the next opportunity (!00% up, 25% down!)

 

If you apply aileron against a dropping wing at or near the stall, the effect is to introduce wash in to that wing - aileron goes down in an attempt to pick the dropping wing up, chord line (drawn from TE to LE) is at an increased angle of attack, induced drag increases and the wing stalls more deeply while the other wing doesn't - classic spin...

 

Some full size gliders often need opposite aileron applied to enter a deliberate spin (e.g. K13)

 

Gemma,  the advice to maintain shallow turns only applies if you don't start adding rudder to get the model turning - again, the basis for the demonstration of a real world incipient spin situation.

 

 

[David Davis]

Well done on the job front Phil!

 

I said that employers are still looking for quality even in a recession. Anyone who can be honest enough to admit a mistake and handy enough to repair the consequences has got to be alright!

 

Just stick the nose down and land down-wind next time if necessary.

 

Don't ask how I found out! 

[Phil May]

Thanks for the feed back, I'm having problems uploading pic's, but heres a couple for now

 

 

 This side of the fuse slotted back together fine, I've sheeted the inside with 1.6 mm lite ply to span the joins for strength ( not to much)  and a bigger area for the glue. The model had a bit of weight on the nose to balance so I'm hoping the weight of the ply will balance out with the removal of the lead.

 The other side is not so luck, so I was able to make a mirror template of this side and will work with that. One of my fellow club members has the same model so I am able to take accurate measurements and a few photos for reference.

 Any advice about this repair is always welcome

        B.P 

[Andy Gates]

You may wish to make the port side of the fuselage slightly longer than the starboard to allow for F1 to be angled enough to give you the required side thrust.

 

Once F1 has been fitted between both repaired sides, any excess on the port side can be sanded off flush.

 

Looks like a great start to the repairs.

[Phil May]

The repair of the crash damage to my P C-9 is coming along well,  still a fair way to go though.  I have made the bottom of the front section of the fuse' removable to allow access to the bigger tank I have installed.

What is the best to recover in, self adhesive solar trim or iron on film.

 Here's a picture of the repair so far.

                         B.P

 

 

 

[Myron Beaumont]

Big Phil

Don't think I would use Solartrim on bare wood .

Then again , I've never tried it

Edited By Myron Beaumont on 06/07/2010 20:47:27

[ken anderson.]

phil-i think they are finished with 'profilm'...

 

  ken anderson ...ne 1..

[Andy Gates]

I would use film not trim, much easier to fix to bare wood and around the curves.

[Phil May]

All ready for the covering now. Going to use film not trim (thanks guys) picking a roll up later from my LMS.

 It may sound sad, but  I really enjoyed repairing this model, when I crashed it my initial reaction was a Viking Funeral!! But when the model was at home and all the front removed it did not look as bad.

 I just hope it flies ok.  

 

       B.P

 

 

[Biggles' Elder Brother - Moderator]

Nice job Phil.

 

Its not surprising at all. There's something very satisfying about repairing a model after a crash. Its sort of...

 

"Aha - you thought you had won Gravity - but no. Thanks to our skills we can rebuild this and it will fly again!" 

 

He he!

 

BEB

[Phil May]

Almost done now, just got to screw the cowl on and touch up a bit of the paint. waiting for the new canopy to arrive ( out of stock at the moment).

One thing I have thought of,  does the rx need replacing after a bump like this received? All appears to be working fine, I have not carried out a proper range test yet, which will obviously be carried out before flying the model.

I was surprised to find that the balance is only a slight bit more nose down than it was