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Glow or Watt? - 4/9/2008 1:39:28 PM   
LDaba



Posts: 178
Joined: 2/8/2002
From: Queens, NY, USA
Status: offline 		I am considering building a twin, a Messerschmitt Bf 110, about 95" wingspan. I have seen several twins buy the farm because one engine cut out. This, to say the least, has a chilling effect on prospective twin builders
My question is with the choice of using either glow engines or electric motors, what would be the better choice, and why? I have no practicle experience with electrics and related charge & support gear. What are your thoughts on this?
Thanks in advance. Happy landings, Tony.



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< Message edited by LDaba -- 4/9/2008 1:40:31 PM >

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RE: Glow or Watt? - 4/9/2008 2:07:16 PM   
evan-RCU



Posts: 2607
Joined: 2/4/2002
From: Charlotte, NC, USA
Status: offline 		Electric but electric is also falible. I have a twin electric and for the first couple minuites its fine then one engine slowly looses power. I have either a bad motor or ESC on one side new from China...

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R/C Anonymous. My name is Evan and I have not flown for 14 hours.

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RE: Glow or Watt? - 4/9/2008 4:13:28 PM   
siddus74



Posts: 137
Joined: 6/29/2004
From: Nottingham, UNITED KINGDOM
Status: offline 		I would go for a pair of OS Glow engines all day every day run slightly rich (not RPM synced). . . Just ensure your plumbing is air tight and treat an engine out as a complete dead stick - throttling back and LANDING.

Oh and only do low flybys on the straight throttling up gradually as soon as you pass yourself up way before the turn.

I stick to those rules religiously and never fly if I spy bubbles in the feed tube when pointed vertically prior to take off.

Scale twins should be glow I think, no modeller I have ever met really appreciated an electric twin it's kind of a non start in my book . . . wheres the skill? Twin Glow models show the ability to build and prepare the model to a hight standard as well as paitence not to fly unless everything is spot one - the key is the plumbing and not trying to fly on one unless you are confident with rudder - the deadstick option is for 'me' always. I have over 50 flights or so on my twin based on the above rules . . .

Happy flying!


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siddus74

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RE: Glow or Watt? - 4/9/2008 5:45:33 PM   
LDaba



Posts: 178
Joined: 2/8/2002
From: Queens, NY, USA
Status: offline 		Siddus: I will admit that a pair of glow engines have a sound that is like music to a modeler's ears.
Do you hot plug your engines? (on board glow battery that provides power to the plugs during flight)
Do employ engine offset to counteract an engine out condition?
I do use rudder to make coordinated turns so using rudder is an integral part of my flying. I'm no hero, I would land if an engine quit but sometimes you are far down wind when it occurs so managing the ship for an approach is necessary.
PS I also have a Spitfire. The 110 would make a great stable mate. Happy landings, Tony.


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RE: Glow or Watt? - 4/9/2008 6:02:57 PM   
siddus74



Posts: 137
Joined: 6/29/2004
From: Nottingham, UNITED KINGDOM
Status: offline 		When I started flying twins I used a gyro but never the onboard glow . . . I found it somehting else to go wrong, I agree with the 'being to far down wind / strip' comment, this is why I start to climb and throttle up from a (low) pass as soon as I am level with myself, this way if you suffer an engine out you may have gained sufficient height and speed to allow for a engine to idle simulated deadstick having enough time to turn back into wind / towards the pitts. What im trying to say is it gives you a greater margin to decide the best course of action. On my single birds I was always doing low circuits even on the turns, on the twins occasionally I find myself doing the same but try and stick by my own rules to ensure that saftely margin is present when it counts. I find it works for me but may not be the case for every one


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RE: Glow or Watt? - 4/9/2008 6:56:04 PM   
Montague



Posts: 4630
Joined: 4/19/2002
From: Laurel, MD,
Status: offline 		With the twin tails on the 110, you could slant the verticals slightly inwards and the engines slightly outwards, both just a couple of degrees, and you'd get a lot of help if you lost an engine. And with the twin tails, you have a rudder directly in the prop blast, which will help with engine-outs. (enlarging the vertical tails a hair would be a good idea as well).

Based on that, I'd think that the 110 might not be a bad plane to handle in an engine out, though you can never really be sure, and there may be stuff I'm missing.

If you're comfortable running glow engines, and don't have deadsticks, then you'll do fine with a glow twin. If you're constantly fighting with your engines, a glow twin might not be a good idea.


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RE: Glow or Watt? - 4/9/2008 8:34:17 PM   
Glacier Girl



Posts: 6849
Joined: 7/9/2004
From: SomewhereIn, PA, USA
Status: offline 		Well as someone who is all electric, even big twins, you also need to look at initial cost for a one time affair. I have at last count six or seven 60 to 120 scale craft, and another dozen or so smaller ones, all using the same packs in different combos, to keep the cost factors down. Even with the China stuff at much lower prices, you are still going to tie up some serious money in a big twin electric bird.

If you are going to have a hangar full of electrics, then cost could be quite reasonable, divided up over several planes. I have three types of packs, 3S2100 for my small stuff, one 4S5000 for my oddball AC47, and a bunch of 3S3700 packs for the bigger birds.

And at least for me, no fuel cans, flight box, glow drivers, tinkering with the motor adjustments, starter, having a helper to hold the plane for throttle run ups, and the clean up afterwards, made me lean towards electric.
Bunch of packs, a charger, and a 12 volt battery(the one in my van), and I'm pretty much good to go.

I can fly one or two of my big birds, then a couple of my smaller ones while the big bird packs charge up, and then start all over again.

But to each their own as to what they fly. As long as they're flying, no matter the power source, it's good enough for me.

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RE: Glow or Watt? - 4/10/2008 1:22:42 PM   
LDaba



Posts: 178
Joined: 2/8/2002
From: Queens, NY, USA
Status: offline 		Thanks to all of you.
I have flown a buddy's Pica Duelist. It had 2-40 engines and retractable landing gear. Besides being fast, it was no different from flying a single engine sport plane of similar dimension. The engines ran for the whole flight.
I guess the main issue is engine reliability. Engine out flying characteristics are certainly a big factor. Cost is a factor. The glow engines sound great when they are running. To me that's a big +. (It's the Walter Mitty in me)
The enlarged fin and rudder make good sense. I'm not clear on why have these slant inward. I can handle a plane deadstick but these were single engine ships. There was no unequal thrust issues.
I have alot to consider.
Here's wishing all of you a 5 mph wind, straight down the long runway. Happy landings, Tony.

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RE: Glow or Watt? - 4/10/2008 3:26:53 PM   
Montague



Posts: 4630
Joined: 4/19/2002
From: Laurel, MD,
Status: offline 		It's not necessary, but if you think about it, if you have twin tails and they are slanted inwards, when one engine quits, the plane basically is going to have automatic rudder input to help compensate for the lost engine.

If the left engine quits and the right engine is still running, what happens? You now get prop blast over the right vertical, but no prop blast on the left one. This makes the right vertical stab and rudder a lot more effective than the left one. If the right vertical stab is canted inwards a little, then it's like having right rudder applied.


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RE: Glow or Watt? - 4/11/2008 1:21:53 AM   
fockewulf37


 

Posts: 1209
Joined: 3/19/2002
From: kannapolis, NC, USA
Status: online 		If you power it right and use the right batteries they are great ... Here is my Wellington I did. I have plenty of power for it and can get a 12 minute run time from the batteries. I adverage about 7-9 minute fligt and very little to no change in the rpm Difference between the motors.....132" wingspan 31 lbs ready to fly...
http://youtube.com/watch?v=xst-WJjlONc


Ty

< Message edited by fockewulf37 -- 4/11/2008 11:41:27 AM >

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RE: Glow or Watt? - 4/11/2008 1:25:43 AM   
fockewulf37


 

Posts: 1209
Joined: 3/19/2002
From: kannapolis, NC, USA
Status: online 		I plan on designing my next twin totally around a electric setup..... If you like the 110 I would do the Don Smith 118" ME 110. and use the same setup I have...

Eflite 110's
CC85HV speed control
2 10 cell A123 packs per motor...
I am running an 18x6 APC wide blade at about 7200

Ty

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RE: Glow or Watt? - 4/11/2008 11:45:40 AM   
fockewulf37


 

Posts: 1209
Joined: 3/19/2002
From: kannapolis, NC, USA
Status: online 		Oh let me add that my cost was about $450 per nacelle for the electric setup..motor, batteries and speed control.. I fugure a higher end gas would have cost me that...

ty

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RE: Glow or Watt? - 4/14/2008 6:20:24 AM   
ram3500-RCU



Posts: 1751
Joined: 8/17/2002
From: n. canton, OH, USA
Status: offline 		I agree with GG on the cost. I was considering electric for my 90" P-38, but opted for glow on this one due to the cost of electric, considering all the other areas that I was already adding cost. For now, my electric will have to be in smaller planes.

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RE: Glow or Watt? - 4/17/2008 6:15:08 PM   
fliir



Posts: 241
Joined: 8/26/2005
From: Belmont, MI, USA
Status: offline 		I think a twin is a toss-up.

Four engines and up - electric is really the way to go: simplifies the setup, easy scale scale cowlings, flip the switch - push the throttle,