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When twins go bad

Old 10-30-2007, 02:33 AM
  #1  
flyingpiggy
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Default When twins go bad

Hi all.
I recently found out that all I have read about single engine flameouts is quite accurate except . . .
1) Its allways the engine on the far side of the model that fails {It dosen't seem to matter which direction the model flys}
2) The is always a LOUD gasser in the sky at the same time

When these 2 conditions are met things start to get interesting : 1st, you can't always see that the prop has stopped if it is on the far side of the model
2nd, you certainly can't hear that something is amiss. The only clue is that the model is getting sluggish and starts to yaw { throttle back NOW } if you don't, things get a bit nasty.
I managed to save the model and set up a passable landing, only to find that my approach was straight toward the parked cars and I had to ground loop the plane to avoid damage to the cars. Go figure, I was in a huge field, I had 360 degrees to chose from and I had to pick the wrong approach track!!!!

P.S
The model is a 7' span Britten Norman Islander with a pair of OS 25s
A real floater

Regards
Dave Read
New Zealand
Old 10-30-2007, 03:51 AM
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siddus74
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Default RE: When twins go bad

Sounds like you had everybodys twin engine worst nightmare, nothing worse than feeling that, 'Oh no, this is going to end in tears feeling, only to realise you are heading towards either a house, car or the pits . . .)

I had my first twin experience last weekend, I bought a Gangster Twin fully radioed with a couple of OS25LA's for £80 . . . I cleaned it up and decided that as I had a spare Futaba GY401 Heli gyro I would put it in just incase . . . (this was after reading Twinmans post on gyros in planes)

Well, after making sure that both engines were suitably running (and putting the gyro in Non- Headng Hold mode), I fired it off up the strip . . . It wasnt point directly into wind but I expected it to weathervane round. But to my delight the model tracked in a dead straight line and took off beautifully, seemed a very strange sight to see it slightly 'side slip' instead of weathervane and run off in a dead stright line. I let a friend have a go after a landing and refill. He did ended up having a flame out after going vertical (due to a air leak around the bung area) and I was amazed on how well it coped, he said 'Oh I think I have lost an engine' then proceeded to go round casually, line her up and bring her in with out any problems, not taking anything from my friend but I am sure that the gyro played it's part . . .
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Old 10-30-2007, 04:40 AM
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NikolayTT
 
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Default RE: When twins go bad

Although many blame the twins to be troublemakers, I would mention that they are pretty good
examination of the Constructors' skills, not so much of the pilots' skills. And also that is making them
such rare event in the sky... As well the Gyro is always nearer and in addtion 10x faster than
a pilot on the ground. Even for the single engine planes the newbies in the RC will get lot more
money saved if the gyros are used widely. Still some "great" pilots are telling that "gyro is a
cheating" - that is one of the most stupid things I have ever heard... and that works "nicely"
for the shopkeepers gains and for distruction of the young pilots' planes.
Old 10-30-2007, 05:29 AM
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siddus74
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Default RE: When twins go bad

I like the " the gyro is closer and 10x faster" . . . nail right on the head! I am going to venture into the twin scene more now definately, and all of them with be fitted with a gyro on the rudder - I think it is a small price to pay considering the time we and money we plough into building these creations. I dont care if the better than sport pilots say it is cheating - if is helps me to safeguard and enjoy my new creation for more than a single flight so be it.!

Old 10-30-2007, 06:10 AM
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Robby
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Default RE: When twins go bad

I personally do not use gyro on twins..
However:
I do think everyone should do what makes them comfortable to have fun...

To date the best way to handle an engine out is the TwinSync...
Should an engine quit the TwinSync will reduce the power to the
other engine even faster than what the gyro can do..
Pull throttle stick all the way back and then you will have normal
throttle control of the running engine... But now you know you
have one engine out and have had time to figure out which one..

Robby


.
Old 10-30-2007, 07:54 AM
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NikolayTT
 
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Default RE: When twins go bad

TwinSync is a nice thing but maybe not faster than gyro anyway and also lot more
complicated to install with those magnets on crakshaft. I have suggested to the
TwinSync-guys to consider taking signal from the pressure fitting via pieso sensor,
that might be more easy to work it out but let see if they come up with such product
modification.

Anyway, Gyro & TwinSync are acting on different paths of that "flying system control"
and thus should lot more secure to emply both of them than only one of them.
Old 10-31-2007, 12:43 PM
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JeffH
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Default RE: When twins go bad

Well the twin-sync is great unless you lose an engine on climb out. YES you can fly out on one engine if you are careful. Of course not all planes will fly out of it, and AoA has something to do with it. If you are past the point of no return, and you lose engine, and the twin-sync yanks your only good engine, you will crash.
Old 10-31-2007, 04:16 PM
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Robby
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Default RE: When twins go bad

Welll, Jeff,
Lets look at this...
With out TwinSync on take off a motor dies,, probably won't notice it in time
and plane goes over right now before you can gain any reasonable control
usually resulting in a destroyed plane... [&o]

Now,, if same scenero were to happen with the TwinSync the running motor
will be pulled back letting you know something is amiss as well as not allowing plane
to rotate into death spiral quickly.. Now you can nose it down and put it in with little
to no damage... Another option now that you know there is a dead motor, and which
one, you can pull throttle stick back and then come back into it as you want regaining
some motor control as well..
Old 11-01-2007, 01:29 AM
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2engsout
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Default RE: When twins go bad

Hi Guys, when an engine fails with a twin sync,,,,the plane slows down with the wings STILL LEVEL. Thats easy to notice even with other planes in the air and engines screaming in the pits! It is by far the safest way to let the pilot know you have an engine issue, period. You are still looking for a place to land,,,but you still have your altitude to work with! As far as losing an engine climbing out right after takeoff,,,,you can't climb on one engine anyway,,,so with a twin sync,,you still have your wings level AND your altitude to work with when you lost an engine..... I'll take my engine outs with my wings level anyday........ Rick
Old 11-01-2007, 05:28 AM
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siddus74
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Default RE: When twins go bad

I would love to try a twin sync, can any body point me in the right direction as to where to buy one from . . . just think, a gyro and a twin sync - always a winner!
Old 11-01-2007, 10:02 AM
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corsaircrazy
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Default RE: When twins go bad

Here is the link to RC Showcase... not sure who else might be a distributor for it.



http://www.rcshowcase.com/html/acces.../twinsync.html

enjoy

CC
Old 11-01-2007, 10:33 AM
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timothy thompson
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Default RE: When twins go bad

E POWER is the answer
Old 11-01-2007, 10:49 AM
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siddus74
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Default RE: When twins go bad

I have thought about epower on many occasions, but the expense of lipos and handling / charging of them still worries me alittle, especially after a friend of mine suffered a fire which almost took out his entire house! . . . I have quizzed others about twin electric's and the response has been more oftern that it would be a bit of a non starter as there is no challange . . . and of course no twin engine sound which I think is half the appeal of twins . . . A twin engine IC model in the air attracts attention no matter what it is > can the same be said for an electric twin ?
Old 11-02-2007, 03:08 PM
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Ghostrider FIN
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Default RE: When twins go bad

gyro, for rudder or aileron? Or maybe both...
Old 11-03-2007, 07:15 PM
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Default RE: When twins go bad

siddus, You tell me. Here are links to my 80" E-Bronco and 60" PROP-DRIVEN S-3 Viking videos.
AEROSCALE


http://www.rcuvideos.com/item/F5YCLXXYW79C2DPW

www.rcuvideos.com/item/MVF08MG7628G8T6N



( fixed link)
Old 11-03-2007, 07:21 PM
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Default RE: When twins go bad

Oooops, left out the fwd slash...........
www.rcuvideos.com/item/F5YCLXXYW79C2DDW
Old 11-03-2007, 08:37 PM
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Tsutomu Mabuchi
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Default RE: When twins go bad

siddus74,

I have been thinking of installing a gyro, Futaba401 for airplane, on rudder
in case of an engine failure. So your report mekes me encouraged to do it.
Thanks.

Tsutomu Mabuchi

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