Nasty wound to my right arm.
|Colin Leighfield||07/08/2019 21:11:28|
5952 forum posts
Hand-launching is second nature if your model aeroplane hobby goes back to the fifties. The recent first two test flights of the Frog Jackdaw were hand-launched because a combination of a rough ground surface and small wheels left no choice. A 60” span, five pound weight plane, held in right hand, transmitter in left, open throttle with teeth and launch. No problem.
On Saturday son James and I went to the airfield for a day’s flying and among our fleet was James’s new HK Durafly Brewster Buffalo. It is a really impressive and beautifully made 36” span model, intended for hand launching with no provision for undercarriage. There are good videos of it on-line and it clearly flies beautifully, and with enough thrust to take it out of your hand vertically it is very fast, in scale terms probably twice as fast as it needs to be flat out. However, you can always back off on the stick. These videos show it being hand-launched without difficulty. Therefore when we came to do the maiden we had no qualms or concerns.
James was going to be pilot and I the launcher. Because of the rotund fuselage it is very hard to grip and my hands aren’t particularly big. Durafly have moulded in two indented grips below the wing to compensate for this. Therefore I grasped the plane there, held in a launch position and James wound the throttle up as I moved to throw it. However the considerable thrust caused something I have never experienced before that caught me completely unawares because it happened in a split second. The plane immediately rotated downward around the pivot point created by my fingers in the indents and the APC propeller ripped through my fore-arm like a circular saw. With hindsight I should have been using my other hand to hold the tail as I launched and if I had, this wouldn’t have happened. However, I hadn’t thought it through or properly identified the risks in advance. When something has never happened before you can be complacent.
A number of club pals were watching because the model looked great and they wanted to see the maiden. There was instant shock and a lot of blood immediately, but thanks to those pals for acting to help and apply first aid quickly, there was an urgent need to control the blood loss. Concerns were such that 999 was dialled and a paramedic from Lichfield arrived quickly, followed shortly by two more in an ambulance. They spent the best part of thirty minutes getting the situation under control and because of the visual mess and concern about possible nerve and ligament damage then drove me the long journey to Royal Stoke University Hospital, which has a specialised serious trauma and orthopaedic unit. Because of extreme pressure in A&E I was on hold for a long time and during the afternoon and evening had two further sudden bleeds that needed rapid support before I finally got onto a trolley bed and finally entered the ward at 05.30 on Sunday. They weren’t able to operate until Monday afternoon, when I was in theatre for forty-five minutes under general anaesthetic. Fortunately, although the muscle was cut, nerves and ligaments were intact. Hopefully after stitches are removed in two weeks the only lasting consequence will be the scar. My planned trip to Brittany on the motorbike has gone for a burton, but fortunately I have been able to re-arrange that to go in two weeks time.
Clearly many will identify the things that I should have known better, but I share the experience because it is not impossible that with this design feature someone else could be caught out. An APC prop at speed is something like a circular saw and it was pointed out to me that if the artery had been severed, it was very close, I would very likely have bled to death. I have put some photos here to clarify what I am describing.
|Martin Fraser||07/08/2019 21:29:19|
35 forum posts
I've known people have a peck from pusher models when hand launching but that's shocking and a wake-up call to us all. Thanks for sharing and hope you have a speedy recovery.
|Colin Leighfield||07/08/2019 21:39:40|
5952 forum posts
Thank you Marty, it’s so easy to take things for granted, but something like this is a real reminder of what can happen so quickly and unexpectedly, with potentially catastrophic consequences. Back up the airfield next Sunday and we’ll find a way to launch this Buffalo safely.
|Chris Bott - Moderator||07/08/2019 21:39:44|
6656 forum posts
Wow Colin that's quite a story and well described.
I don't think I've ever considered that possibility. We have so much instant power availsble these days don't we? I'm sure that posting here will save others from the same scenario at some point or other.
Very best wishes for a speedy recovery.
|Martin Harris||07/08/2019 21:39:54|
8806 forum posts
Something very similar occurred during a hand launch of a 1/12 scale combat model - the pilot was lucky to escape with a trip to hospital and some stitches - to his great credit, he returned at lunchtime to continue with the meeting.
It's a very graphic warning - it might be far safer to perform an underarm lob if you are launching with one hand.
|Bob Cotsford||07/08/2019 21:44:22|
7973 forum posts
A lucky escape Colin, as you say that could have been so much worse. With the power level that you report and two 'lips' with which to hold the model (in)securely you didn't stand much of a chance really.
|Colin Leighfield||07/08/2019 21:46:58|
5952 forum posts
Thanks Chris and thanks again Marty. If it helps to prevent only one more such experience it will have been worth it. I will do my best not to repeat the event.
|Colin Leighfield||07/08/2019 21:55:48|
5952 forum posts
Hi Bob. It was lucky really. As Chris says, the instant power that we take so much for granted now is way beyond what we were used to years ago. I had a Pilot Models Spitfire 24 that I built about forty years ago as a Seafire 47. That had no undercarriage and because of difficulty in holding that to hand-launch, I made a scale centre-line drop tank that served as a hand-hold. With the OS25 flat out, it never showed any sign of rotating in the launch position in the way that the Buffalo did. That was probably because of the shape of the drop tank, the circular indentations on the Buffalo offer no resistance at all to such a thing happening. You would need a far stronger grip than I have to prevent it.
|Peter Christy||07/08/2019 22:26:58|
|1554 forum posts|
Wow! A nasty experience, and thank you for your honest explanation of what went wrong! It may well prevent someone else from making the same mistake.
Many years ago I had an experience with certain similarities. My son was learning to fly at the time, and I had obtained, from another club member, a 2 channel glider, with a power pod on top. An AM 15 diesel was fitted to the pod, and duly started. Now I'd never had a model with a power pod before, and had got into the habit of making sure my hands moved in a wide arc behind the nose of a powered model when the engine was running - except in this case, that was exactly where the prop was!
Cue a trip to A & E for stitches. Much hilarity from the nurses: "Who's the one who has cut himself on a toy aeroplane, then?"!
Lesson learned and not repeated!
|Colin Leighfield||07/08/2019 22:40:17|
5952 forum posts
Thanks Peter. I must confess that about forty years ago I stretched across my Slim Jim when the Fox 40 was flat out. I got too close to the prop and finished up with a few stitches then! I have to admit though it wan’t in this league.
|Martin Harris||07/08/2019 23:07:38|
8806 forum posts
Although not a factor in your unfortunate incident Colin, powerful electric motors are not to be trifled with. it gives me the "willies" when I see people connecting electric models with their hands through the prop arc. While disarming switches/mixes are a great idea, reliance on them is an accident waiting to happen.
Peter's story of amusing the nurses reminded me of a similar incident with a Cessna 337 model where the owner reached through the rear prop arc to remove the glow clip.
...which also reminds me of how I found out how dangerous pusher props can be while adjusting needle valves. Back in the mid 70s when a .20 was an average sized engine, I sliced open the fleshy bit at the base of my right thumb with one. Lucky it was only a small engine...
After some field repairs, I restarted the engine and started adjusting it with my left hand. Bang! More bandaging on my left hand and brain finally engaged, I realised that the prop was coming at a cutting angle instead of the usual knuckle slap from getting too close to a tractor prop. I was extremely careful on the third attempt!
I still have the scars to remind me to steer clear of pushers.
|Paul Marsh||07/08/2019 23:20:20|
3708 forum posts
I've launched many models before, the most scariest one was this model. In windy days the model can easily get ripped from your grip, so holding the wing, steadying it is the best way.
Get well soon, I've cut my hand years ago and its easy to think the prop isn't there, a bit of brain fade all it takes.
Scary hand launch model, 2 SC 52's!
|john stones 1||07/08/2019 23:28:45|
10592 forum posts
|Geoff Sleath||08/08/2019 00:14:17|
3363 forum posts
Perhaps it's fortunate that I physically can't hand launch effectively. I no longer have sufficient control (or strength) in either of my arms - my left is strongest but I am right handed so ...
I've noticed that downward pull when I've held a model when testing but it never occurred to me the potential for such a nasty injury. Thanks for the heads up and get well soon.
|J D 8||08/08/2019 00:16:41|
1259 forum posts
Just put together a Parkzone F4F Wildcat with similar rotund body and will be taking extra care after your experience Col.
Those grip points on the Buffalo may not be such a good idea. The Wildcat has none so you have to hold it behind the wing where the fuselage is narrower and your hand can fit around.
All the best with your recovery. John.
|Colin Leighfield||08/08/2019 08:03:08|
5952 forum posts
Thanks again chaps for all of this concern and interest. Perhaps the most significant realisation is that beyond our common experiences of painful but fixable damage around hands and fingers, we are:-
(1) now commonly operating models with powerful electric motors that don’t stop delivering power when we stall them.
(2) using efficient propellers such as APC that are made from a very rigid plastic and are sharp enough to cut you even when stationary.
These combined put us physically very close to a cutting tool that in contact with the fleshier parts of the body is capable in an instant of cutting through full thickness down to the bone, passing through muscle, ligaments, veins and arteries on the way. The potential consequences of that don’t need explaining and I am very aware from this experience of just how lucky I have been.
I don’t want it happening to anybody else.
|Peter Miller||08/08/2019 09:08:49|
10183 forum posts
Very very nasty indeed. Glad that there will be no lasting damage.
Over the years I have seen some very nasty accidents caused by propellers in unusual places, even had one myself.
Now I tend to be a bit paranoid and refuse to handle a model where the prop is not right at the front of the model in the normal place.
Two examples to prove the point.
My Don Kichot Polish home built has the prop (My beautiful hand carved beech 11" pusher prop) 1/2" behind the trailing edge of the wing. A friend went to pick it up and carry it out to the take off area. He ran his hand down the trailing ege of the wing. 11 stitches to put his finger together. It also broke my prop!!!
Example two. Someone built a control line model of that WWI Spad with the gun position in front of the propeller. The propeller was in a recess in the leading edge of the wing.
In those day we flew a lot of control line biplanes and it was normal to pick the model up by hooking ones finger under the leading edge of the wing to carry it out with the engine running. Need I say more?
Edited By Peter Miller on 08/08/2019 09:09:49
|ROSS MANSELL 1||08/08/2019 09:22:56|
10 forum posts
THAT is not nice at all..my sympathy!. Perhaps a Tranny tray (neck strap/tray type) will help..save using the teeth on the throttle !! The electric jobs ..they don't stop running when they hit a hand like the old days of diesel or petrol.
Edited By ROSS MANSELL 1 on 08/08/2019 09:25:01
1541 forum posts
I managed to draw blood on several occasions when launching 'Wild Wing' delta powered by a speed 400 fitted with a 'Guntther' prop so I can only imagine how painful that would have been. Hope all is soon well.
254 forum posts
Ouch baby! Very ouch!
@John I have a PZ Wildcat. I find I can hold the fuselage under the wing / cg in the usual manner without any issues, It gets away with a medium push and around 50% throttle no problems at all.
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