Bigshark

Just to try something totally different, I am starting to acquire the stuff to build a small Vickers Wellinton bomber from plans. The plans are from 1980 and show rediculously large servos by todays standards. They also call for you to fabricate your own fuel tanks and turn blanks for the cowls using your wood lathe instead of contacting fiberglass specialties.

In any case the plans call for .10 sized engines which are probably a good deal scarcer today than they've been in the past. Not that Tower is the only place, but they only stock OS and Magnums in this size. Keeping price in mind as well as reliability who's got the best?

I should also point out that 6 oz is the absolute maximum tank size for each engine. The nacelles are tiny and 4 oz would be better.

scott17

OS .10s are great and 2.5 oz. would be plenty!

Ram Jet

I have a nice Enya .09 new in box and I haven't run it yet. If it's built as well as the Enya .19 that I have run it should be an excellent engine.

Bill

rainedave

My Feedback: (1)

I fly a .15-size model with a 2oz. tank. Four ozs will go a long, long way with a .10. I think the OS La's would be your best bet. They are relatively light and very reliable. Plus, the break in is quick and easy. But, I would use .15's. You're only saving a little bit of weight with the .10's, but your losing quite a bit of power.

David

Sport_Pilot

TT .10 would be good. As would their .15. And possibly a Fox .15.

AMB

As stated the TT10 or OS10LA good reliable engines I have both in some electric conversions and I did put davis diesel heads on them almost twice as long on a tank of fuel and will turn a larger prop than glow either way your best bet martin

NM2K

My Feedback: (14)

I don't know if they replaced the TT .10 with another size recently. I did buy a few .10 and .15 sized TT engines before the change. Some new, some used. Just don't forget to run all castor oil fuel with these plain bushing engines.


Ed Cregger

huck1199

How about a K&B .18 at 8oz with muffler. $89. Fits in mounts for most .15's. Check out at MECOA https://shop.mecoa.com/shopdisplayproducts.asp?id=22

asmund

This one will blow the doors off all the rest, and the quality is top notch and it runs it`s best on 0-5% nitro.
Maybe not the lightest of 15`s but I`m pretty sure it is the most powerful one

http://www.leikvold.no/index.php?men...=60&vare_id=41

buzzard bait

Wait a minute, we're talking about a small scale Wellington here! Scale speed would probably be about 20 mph. If the original model flew with .10s using heavy old equipment, more power is not what is needed. This is the Model Aviation plan from about the 1980s, right?

It will be great with any of the OS .10s (LA, FP, FSR), or TT .10 GP, or Enya .09. You can pick these up on auction very cheap, or buy new from Tower (OS), Radical RC (TT). I'm not sure about where to buy Enya .09s new. But they swing 8 inch props easily. More power will give you a faster, less realistic throttle response, for no benefit.

If you really want to cruise around awhile, a Hayes 3 oz. will keep you going about as long as you can stand.

Great project! Keep us posted. Build it light, fly it slow - it will be a wonderful sight in the air.

Jim

NM2K

My Feedback: (14)

For years now MVVS agents have been telling me that glow and Diesel model engines are not being made at the MVVS factory. Are these engines NOS?


Ed Cregger

NM2K

My Feedback: (14)

Mentioning scale speed will get a huge debate going on here. <G>

Years ago, either on RCU, rec.models.rc.air or rconline, debate over scale speed raged for months. Lots of wonderful information was revealed. It turns out that there are many, many factors to take into consideration. If anyone knows where we can find that debate, please pass along the location to us. TIA

I like the OS and TT plain bearing .10 and .15 sized engines. When dealing with two to four engines, the last thing you want to do is to have to worry about four sets of ball bearings. I have found the small airbleed carb equipped model engines to be just as reliable at idling/transitioning/WOT as the larger ball bearing versions. This is as long as they are either upright or side mounted, your fuel contains 20 to 25% castor oil and 15% nitromethane and the engines have had a bit of break-in time under their belts.

Whether or not the engines are the most powerful for their displacement really isn't important, since there is no displacement limit being imposed. If a .10 won't do it, replace it with a .15. If a .15 won't do it, replace it with a .20 and so on.

I would love to see a build series of this model, if the OP doesn't mind the extra work.

I just reread the original thread, it's a twin. That should be easy to accomplish, with due diligence, etc.


Ed Cregger

asmund

Yes, all the small MVVS engines are discontinued I`m afraid, but there`s some still available on the shelf in some places. This Norwegian dealer still have most, if not the whole production line

NM2K

My Feedback: (14)

Every time I go to order a K&B .18 airplane engine, they are out of stock, so I've never ran one. Wish I could catch up with one someday.


Ed Cregger

huck1199

Ed,

The 8801 .18 shows 'good' now for availability.

buzzard bait

Ed, I'm very familiar with that scale speed "debate". But as Gordon Whitehead says in his book on scale models, there is really only one definition of scale speed that can make a model plane look like the full scale plane in the air. Yes, with maneuvers there are dynamic considerations, but if you cater to those then the plane will still look like it is going too fast, even if control responses are technically more accurate.

I'm certainly not a stickler for scale speed, but it's hard for a model bomber to capture the majestic look of the full size in the air. If this is the MA design, the model is somewhere around 1/15th scale; the full scale plane couldn't have flown much over 200 mph. Even two .10s will have to be throttled well back to get a nice looking flight, and even then it will be going faster than scale speed. The designer says it flies well on one .10, with the other one out. The .10s give it plenty of power. Eric Clutton flies a scale Liberator of the same size as this Wellington on two .03 diesels (he leaves the extra nacelles unpowered).

So often when people ask what engine to use, everyone recommends more than the designer calls for. It seems like a reflex reaction, and on a scale model like this, I think the builder will be happier sticking to the original intention. Jim

Ed_Moorman

My Feedback: (1)

My buddy, who builds, but doiesn't fly, and I are on our 25th twin. In 2-strokes, we have tried Thunder Tiger, GMS, Magnum and OS. We have ditched all of them except OS. I would recommend a pair of OS .25LAs.

From my experience, engine reliability is the one greatest factor to be considered in a twin. All the other brands have given me a lot of practice landing single engine. We have learned not to tune them too lean. Always set them so they leave a little smoke trail.

Another thing, forget synching them up. Tune each individually, then refuel and crank both and fly.

Drop me an e-mail if you need more info.

scott17

The plans call for a pair of .10s and you suggest a pair of .25 LAs? I don't get it.......

Bone

Very, very sound advice. We would all do well to stop & re-read Ed's advice again.

I practice what Ed says. I've now had over 60 flights on my twin engine model & the only dead sticks I've had is when I have disregarded the fuel flight timer on the Tx.......[:@]

scott17

Do you also use 2.5 X larger engine than the plans specify?

buzzard bait

Except that it came from Ed, I would have assumed the .25 advice was a troll.

Bigshark was asking for advice on buying a .10 engine, not asking people to second guess the designer of the plane he is building.

People need to see the actual construction article before giving advice like this, no matter what their experience and reputation. After seeing the pictures and the plans and reading what the designer wrote, no one would suggest a .25 for this plane.

As Bigshark pointed out, the nacelles are very small. The OS .10s used by the author barely fit. The plane is lightly constructed. The author wrote a fine article with plenty of construction and flying advice.

People who do not normally fly with small engines assume they are finicky and unreliable. But the .09 to .10 size engines are as solid and reliable as .25s or any others.

Jim

asmund

Ok, then he might look for something really small, light, reliable and powerfull. May I dare to suggest a couple of Norvel .061`s, or even the Norvel .074?? They are really compact and much lighter than a .10 or .15 but produce about the same power. These engines are a little difficult to obtain, but show up on the "big auction" site from time to time.
I fly a Norvel Big Mig .061 and it has the power and throttle response to easily hover my 400 gram 3-D plane down on the deck, totally dependable

Tomorrow I will test my AP .061 in the same plane. I got this cheap chinese copy of the Norvel to find out if it is any good, and can replace my Norvel after it is gone. It runs great on the bench and I`m hoping it will approach the Norvel in terms of power and transition

Ed_Moorman

My Feedback: (1)

I may have mistakenly thought the question was for a .10-.20 sized engine. In that case, since the LA series tends to be low power, the .25LA ought to be just right. If you really want a .10, try the OS .15LA.

Say what you will about the LA series, and I don't have very many of them (2-.46 & 2-.65) and don't fly them very much, but they are reliable. I have flown too many different twins and seen too many people crash twins to recommend anything above reliability unless the flier is an expert. In flying those 4 LAs and my buddy's 2 LA .40s he had on a canard, I have had 1 in flight failure and I don't count that one. On the test flight of the plane powered by the 2 OS .65LAs, one throttle cable came loose and the carb rolled closed and the engine shut down. I call that maintenance error, my fault, and not the engine. Other than that, I have never had one of those "sorry," "low power" LAs on a twin fail in flight. They aren't 3D engines, but they do keep on chugging unless you try to wind them up like an FX.

The photo shows the first test flight landing where the throttle cable came loose, allowing the engine to shot down.

buzzard bait

Sorry Ed, you're right, he did say .10 - .20 in the heading. From the article it's clear that a pair of LA .10s would fit nicely in the nacelles and provide power like the original. 15s would be usable, but would stick out more. I like the LAs too.

The author used 7x4 props, but the MA 8x3 would be worth trying. He said that landings were long. The 8x3 would slow it down more, and probably give a little finer speed control.

Pretty twin in your photo. I'm curious as to what it is.

Jim

Bigshark

Wow. Thanks for all the replies. I did have the thought running through my brain to up the displacement on the engines a bit. The plans are Frank Baker's from MA in 1980 or so and do show really huge radio gear and from the build article the plane sounds under powered by today's standards. Perhaps doubling the engine displacement to .20 would be total overkill.

As to scale speed and flying, I'm not in this build to go hovering my bomber over the runway. I do like to have a bit of reserve thrust available though, because I'm not the worlds best pilot. Even with two engines this plan looks more like a sailplane than a warbird so I may be a bit paranoid.

I am thinking of going with someone's .15 displacement. I should be able to tuck the slightly longer .15s under the cowls given that I plan to build them a bit wider at the tips to look more like the later marks of the Wellington. I also plan to try my hand at vacuforming the later models of front and back turrets.

Actually, looking at the os la .10 and .15 the price is similiar to the TT 18 and about $10 more than the magnum .15....hmmm. Any one know a good three blade prop for the OS .10 or 15? Not that I really need to go scale there. I've never owned an OS because the price always seemed to be higher than the payoff. This may be their chance to get at me

Thanks to everyone.

And to Ed, I may try to make this my first build thread at some point. I'll keep you posted.