russellqueen

I am building a GP cub 60 clipped wing version and am putting a saito 100 Twin in it, or so I thought. After assembling the fuse with the firewall/sides, etc, I went to place my engine on the pre dirlled holes that I matched up before installing the firewall, and the engine mount came short of contacting the firewall by about 3/4'' because the cylinder heads hit the front of the fuse sides.

My question is do I laminate more plywood onto the firewall to make up the space, or cut the sides of the fuse so that the cylinder heads clear. Does saito make an engine mount spacer??

Please help!!

THANKS
RUSS

ghendrix01

My Feedback: (1)

Russ,

As long as adding the extra plywood spacers places the prop hub at the correct location relative to the cowl, then yes use them. I did the same thing when I built my GP Super Skybolt and used the same engine. I think I had to add 1 inch of spacers to get it to the proper location at the front of the cowl.

George

russellqueen

did you just epoxy the plywood?, and what do you do about the mounting screws, because they will be too short?

THanks for the input!!

RUSS

russellqueen

I have to add 2 1/2 " to get the engine to match up with where it exits the cowl. There has got to be a better way than stacking that much wood in the nose???

I am dying trying to figure this one out, because either way I am screwed, being really nose heavy with 2 1/2 inches of plywood in front of the firewall or cutting the cowl off 2 1/2 inches and the fuse about 1 " making the thing pug nosed.

I thought this engine was a good choice for this kit. How have others done it????

PLEASE HELP!!!!

RUSS

ghendrix01

My Feedback: (1)

Russ,

I had to find some longer screws to mount my engine. I'm not sure where you can get longer screws, but I did see some posts about longer screws elsewhere on this forum. Maybe someone else can give a link to someplace that will have long enough screws. I was able to get some from where I work. They were stator bolts from induction motors. I don't feel adding the plywood would add that much extra weight but thats just my opinion.

I found two links for longer screws:
http://www.microfasteners.com/
http://www.fastener-express.com/

George

russellqueen

Someone gave me the idea to use broom stick handles cut to length with holes drilled for 3'' bolts to save on weight. I guess I I'll have to give it a try and see. Any other thoughts let me know!!

got the bolts on boltdepot.com
Thanks
RUSS

IFR

My Feedback: (1)

I had a Saito 100 twin in my .40 GP Cub and it flew great. To overcome the engine spacing issue I stacked 1/4" ply squares, slightly large than the back of the engine, until I got the desired thickness, cut the centers out of all the ply pieces, with the exception on the outside piece, then epoxied them together. Ended up with a relatively light box on which to mount the engine. Drilled holes in the box to route the fuel, vent, and crankcase breather tubs. Since the Saito 100 mounts directly to the firewall a trip to the local hardware store got the appropriate length screws and lug bolts to bolt the engine and block to the firewall with the same 4 screws. The firewall will set the box at the appropriate thrust angle. To fit the cowl I cut it into three pieces, two being small squares that fit to the top and back of the cylinder heads and one large piece that enclosed the entire bottom half, front, top of the engine from the middle of the cylinders forward, and a strip to go between the needle valves to secure the large piece at the top. This way I got a nice snug fit around the cylinder heads and could easily remove it for engine access. All done it looked like a real Cub engine set up. The twin makes a sweet sounding Cub and at low throttle flies very scale.

goneflyn

Hi Russell,

The twin 100 on a cub sounds great! I love cubs but think they indeed need a twin to be really "scale". The suggestions above sound pretty good, but I understand your concern about the weight up front--especially with the twin. The engine box sounds like the best way to go. You can see a picture of a similar box on the "Kit Building" forum under "Do you drink beer?" Building up the box is not difficult, not sure about the broom handle thing though. Broom handles aren't always that strong. If you have an thrust variations (up/right) then don't forget to check the engine/cowl alignment before you drill the holes for the engine mount. I switched to a RCV from a .46 OS engine on my P-51 and the nose had to be rebuilt because of the difference in length--but you probably already new that :-). Good luck.

btw, if you could send a sound bite of the twin 100, I think that would be great <big grin>

ketil

I had the same problem with my Goldberg cub with a saito 90 twin.
I went in the hobbystore and bought 4 engine rubber mounts,fit perfectly fore the goldberg cub.

don olsen

My Feedback: (2)

go ahead and put the spacers in there just be sure to have the bolts go through the firewall I had a OS120 twin in my gp 60 cub it was wonderful you will love the way itflys and the sound is so cool on slow passes by the way they ussualy come out tail heavy so the added weight is good

russellqueen

Thanks for the help guys. I think that the plywood sounds a lot better than broomstick handles, and if I cut out the center that will definately ease my mind on the weight issue. If anyone has any more tips for the kit then let me know!!!

Thanks
RUSS