VetteV12

I found a cheap $20 .60 sizeYak (I think)made by either nitro planes or hobby kingat my LHS that was previosly converted to electric. I'm not a fan of large scale electric anything, so I'm trying to convert it back to glow. The only issue I see is that the engine box was cut off and a metal one was installed for the electric motor. Do I need to try and build a new engine box/stand off or can I just use a really long engine mount? Any help in the matter would be quite appreciative.

JohnBuckner

My Feedback: (1)

AH Vette please let me applaud you your decision even a somewhat controversial one in these times of mass internet pushs to convert the world[

Now yes first it can and should be done if thats what you like, as to the specific of how exactly to go about it and whether or not you need to build a motor box is almost impossible to answer with what we know now.

If at all you possible post a picture of the front end showing the firewall and the most important thing you will have to is decide where your target CG is to be placed. Following this is just how far forward is the engine going to have to be to acheve your predetermined CG. This distance will allow decisions to be made on the need for a simple box or not.

What I mean by predetermined is for that airplane I would actually recommend a 25% mac as determined by the very simple and quick midspan averaging method. This can be far easier and requires no computer as well as allows you to decide what CG you want.

What I would not reccomend is for you to to waste time looking for manuals and such if the airplane is from Nitro or that Hong Kong place as information that accompanys their product is almost always wrong at best and dangerous to the survival of the airplane (bingo for them) at worst.


Indeed there are four stoke engine mounts that also fit two stroke sixties that will put the engine out forward a limited distance and in addition often a layer or two behind the mount will add to that but agine more info is needed and especially that photo.

John

VetteV12

Haha, yeah this world has changed a LOT in the short 25yrs I've lived on it.

JohnBuckner

My Feedback: (1)

OK so using that mount with the engine mounted how much forward of the firewall will that mounts firewall face need to be in front of the firewall or similar structure? Another way of putting it would be if you knew how much of the box was removed.

If there is a cowl involved and it is the original you can position the propshafts drive washer in the approximate location when the cowl is mounted and approximate how much of the box is missing.

I have done some electric to glow conversions where it was only neccessary to laminate a firewall to existing sturcture. It all depends on what ya got.

John

VetteV12

I have no cowl or reference line to go off of, I'm purely guessing. But what you're saying is that it's only necessary to do this for CG purposes? If so I'll fly tail heavy, I prefer it slightly tail heavy anyway.

Gray Beard

My Feedback: (-1)

If it's a nitro planes and it looks like a 60 size it may be what they called there 90 size, they were pretty small to call a 90 but they did it. Anyway, it may not have had an engine box? Most of the Extras and YAKs I had assembled for people from Nitro just had a fire wall and you used a motor mount. Even using four strokes like the Saito 100 they still needed added weight up front. Every one I assembled was very tail heavy. Very nice flying planes though. For 20 beans you did OK if it's in good shape. It did come with a glass cowl though and they may have a replacement?

JohnBuckner

My Feedback: (1)

I agree with Grey Beard twenty bucks could indeed be a great buy but if you truly mean what you said above this likely would be a rather poor decision on your part especially so since this is a Nitro Planes product and the airplane may well not live long.

The idea so many people have that a Yak is a Yak or a Cub is a Cub with no consideration at all to the litterally hundreds of different designs Is a big mistake. Just because one china factory calls an airplane a Yak and it may resemble such does in no way mean its going to fly like another companys offering that you hear all the wonderful things about.

Yes and since you are dealing with so many unknowns your first consideration Should most definately be CG in cases like this and its so easy Ya don,t even need a computer And this is a great place to start learning about such things with lots of help but if you get impatient and just want put it together and dismiss CG well a Yak is not neccessarily a Yak.

John

Gray Beard

My Feedback: (-1)

Last one I assembled for someone was there Extra. I installed a Saito 100 in it and the plane required a couple ounces of lead in the nose just to get it close enough to the CG to fly. Nitro planes is just another distributor of planes under there name. The same plane can be sold by a number of companies and all will have the same problems. Most come out way too tail heavy to ever fly at all. Look at the wing and fuse of your plane, it may have the CG marked? I always mark the CG on the planes I build or assemble. If not, use one of the on line CG calculators. If you don't get it right it will be a problem. They come out a lot tail heavy and just mounting all the gear up front isn't enough. Your call, nuff said. It's only 20 bucks and could be an eye opener for you.