Venus 40 balancing question
 

I've had the Venus finished for about 4 months now, but haven't taken it up yet. Been practicing and getting experience on my Sky Raider II first. Now that the weather is nicer, days longer etc. I just started the final adjustments on the Venus as well as breaking in the engine.

Getting the Venus to balance according to the manual, I need to add 5 oz of weight to the engine block!!
This seems like a lot. Is this normal? I already have the battery showed up as far as it goes under the tank. The engine I'm using is the Mangum 52-XLS.

How do I even fasten 5 ounzes of lead up front?

Thanks,

tycho

RE: Venus 40 balancing question
 

Trying one more time. Anybody have any advice?

RE: Venus 40 balancing question
 

Curious Ive got a 70 ASP four stroke in mine which is probably 140 grams heavier than your magnum 52 and to balance it the battery is installed behind the servo tray, I am suprised that yours does not balance with the battery right forward under the tank. The c/g should be 4 & 5/8" behind leading edge of wing adjacent to fuselage. Useful weight can be added to nose if required by using an alloy spinner instead of kit supplied one. If you have to add more weight make sure its firmly attached to bulkhead of model with sheet metal screws, epoxy or silicone.

RE: Venus 40 balancing question
 

Yes, I'm surprised too that it's so tail heavy. A review of the Venus 40 available on RCU shows the author balancing it with the battery around CG with a OS 50sx, which is comparable in weight to the Magnum. I am measuring 4-5/8 behind the leading edge, or if I remember correctly 118mm, which being from Europe, feels more familiar to me.

I don't understand why it's soo tail heavy. All I did was glue the tail feathers on.
Oh, well...[:o]

-tychoc

RE: Venus 40 balancing question
 

I just weighed some flight packs, the regular AA type come in at around 100 grams but the A type packs are about 140 so perhaps that will help, My motor by the way is quite well forward the cowl only overlaps the fuselage by 1/4", I understand theres an ammended distance to set motor at on Great Planes website but I needed to set mine forward for firewall clearance as its a fourstroke.

RE: Venus 40 balancing question
 

Did you balance your Venus upside down - if you did and it still needs the weight go get a dubro spinner nut - they come in 1 oz aluminum and a heavier brass filled aluminum 3 oz nut to hold your prop on and help to balance the plane.

RE: Venus 40 balancing question
 

Tycho,

I have a Venus 40 with an OS50SX. My 1650 mAhr battery is in the compartment under the fuel tank and the plane is blanced per the manual. I do have the engine in the updated position since I built mine last August.

With the Cg in the recommended location, I find this plane fairly easy to land compared to some of my other aerobats. Just keep a little power on until it settles and it shouldn't bite you.

Greg

RE: Venus 40 balancing question
 

On planes that I had to add a lot of weight to the nose I put a heavy hub on for more weight. This either allowed me to move the battery back some or have to add less lead.

RE: Venus 40 balancing question
 

Yes, I did balance it upside down and I need 5 1/4 oz for it to balance according to the manual. This is with my 1400mAh battery up in the compartment under the fuel tank.

With the Dubro spinner nut, can you still use a regular spinner on top?

thanks,

tychoc

RE: Venus 40 balancing question
 

I did put a plastic spinner over the dubro spinner nut on one of my planes - it depends on the size of the spinner. just for info most of the dubro spinner nuts are available in colors also if it doesnt fit.

RE: Venus 40 balancing question
 

Just out of curiosity what did you glue your tail feathers on with?

RE: Venus 40 balancing question
 

I used 30 min epoxy. Same procedure I've used (and amount) on my other ARFs that all have been close to the correct CG.

-tychoc

RE: Venus 40 balancing question
 

Wasnt trying to be nasty just looking for clues tychoc, personally used cyano but unless you used a lot of epoxy i.e about an ounce and a half. it wouldnt make that much difference. I am really at a loss to explain the tail heavy result for your Venus but as my bird flies very nicely with 140 grams of Chinas finest up front I would think yours will be ok carrying the ballast

RE: Venus 40 balancing question
 

I checked my 2 inch spinner - a dubro spinner nut will not fit under it. I believe that is the size of the Venus spinner.

RE: Venus 40 balancing question
 

davej78: I didn't interpret your comment as nasty at all[8D] I, myself, am starting to wonder if I could have messed something up, but there really isn't much that can go wrong when all I do is glue the tail feathers on and put the radio gear in.

delman: I believe the spinner is 2.5 inches, but I'm not 100% sure. How does the starter work with the spinner nut as opposed to a regular spinner. Do you need a different rubber insert in the starter?

Thanks for all your suggestions and ideas. I guess in the end they must have used some heavy balsa in the back to make it that tail heavy. I'll stop by the LHS tonight and check out the spinner nut.

-tychoc

RE: Venus 40 balancing question
 

Tychoc,

There must be something way different in how your Venus was constructed vs. mine. I use 30 minute epoxy (not CA) on the tail feathers just as you did.

I certainly was not aware that there would be that much variation in ARF's. Probably nothing you can do about it, but good to know for future reference.

Greg

RE: Venus 40 balancing question
 

Tychoc,

I've been flying my Venus 40 since last spring. mine balanced just fine by moving my battery. I'm using a O.S. 46FX mounted at the end (forward edge) of the motor mounts. I land mine a little on the hot side but be soft on your landings as the stock landing gear is weak (they bend real easy). The airplane is a blast to fly.

RE: Venus 40 balancing question
 

The starter works the same on the regular dubro spinner nut as with a spinner. The standard starter cone usually works fine. After the cone started to wear I replaced it with a softer blue cone insert.

RE: Venus 40 balancing question
 

I bought the 3oz spinner nut yesterday and also got a 2.5 in spinner. The nut fit inside this spinner and I added another 1 1/4 oz lead to the engine mount to make it balance. I also took the foam around the battery off so that I could place it as far as possible up front under the tank compartment.

I'll maiden her next week.

tnx, tycho

RE: Venus 40 balancing question
 

I bought the 3oz spinner nut yesterday and also got a 2.5 in spinner. The nut fit inside this spinner and I added another 1 1/4 oz lead to the engine mount to make it balance. I also took the foam around the battery off so that I could place it as far as possible up front under the tank compartment.

I'll maiden her next week.

tnx, tycho

RE: Venus 40 balancing question
 

Good luck on your first flight - after flying in inverted you might be able to take off some of the weight if you balanced at fwd cg limit.

RE: Venus 40 balancing question
 

I also have one with OS 46FX at front end of motor mount, alum spinner, and battery was behind fuel tank. I also used epoxy for tail feathers and had no trouble with balancing the bird. The plane is a lightweight so little things like using light tailwheel, light pushrods and heavier main wheels may help bring your balance forward. Your magnum is a screamer so you won't need to worry about reserve power even with all that extra weight. I can get unlimited vertical with just OS 46. Don't forget to get flaperon mix turned on so you can so this bird to a walk on landing to show off to your buddies. Mine can land slower than a trainer with flaperons on.[:-]

RE: Venus 40 balancing question
 

kmtranmd: I've got the Magnum broken in now, and you're right, it's a screamer. What size propeller should I go with? Right now I have a 11x7.
I did turn on the flaperon, but I have never used it before so I probably will try it out a little later. When I experimented with it on the ground, I felt it was hard to twist the little knob such that both the ailerons would be centered again. Is this not a concern since you only use flaperons upon landing and can reset it before taking it up again? I'm using a Futaba 6XAs radio.

Everything should be ready now. I've set up the dual rates and correct throws, balanced the propeller, balanced the bird itself..., and broken in the Magnum. Hopefully we'll get some nice weather next week so that I can maiden it.

-tycho

RE: Venus 40 balancing question
 

My Magnum 52 XLS is also new, just broken in to be installed in Kangke F20 Tiger Shark. I will start with APC 10x8 and try to keep RPM around 14K because I don't know how well this motor can handle higher RPM. 11x7 should be OK. I used that with my OS 46 and it was OK. Regarding flaperon, save it until you get used to the bird. Yes, I reset flaperon after landing. This is important, you don't want to take off with flaperons on. Neutral should be at one extreme of dial throw. Low speed landing can be more tricky if you don't get it lined up well. Plane tends to be more wobbly with aileron input and easier to stall. But this bird is really forgiving. Nose only drops for about 10 feet and it wants to fly again.

RE: Venus 40 balancing question
 

Tychoc just occured to me did you put in spacer on firewall as in instructions? 46 and 53 ASP (Magnum) are pretty similar in weight/ overall length so presumeably would need same spacer.