hey guys,

i have the venus 40 arf with the os 40la. my plane is VERY tail heavy it seems. i'm using the great planes balancer. i have to use between 7 and 10 oz. i know this has got to be way to much. and this is the batt and rec as far forward as i can get them. i know the 40la does not have enough power to compesate for the weight without turnig her into a flying brick. any help would great.

thanks guys

That seems like too much weight to me too. I had one with an OS52 four stroke that I was able to balance without anding any weight The 52 is only about two ounces heavier than the LA. After reading your post, I found a back issue of RCM with a Venus report in it where they used a 46LA. They said in the article that they didn't add any weight.

The manual suggests starting at 4-5/8" back from the leading edge next to the fuselage for a starting point. I think mine ended up at about 4-3/4" back. I used the supplied pushrods, but changed the tailwheel for a Sullivan. I don't know for certain, but I think the Sullivan probably weighs about the same as the supplied unit.

Are you sure you are measuring in the correct place, just next to the fuselage?

By the way, don't let the CG get too much farther back than the manual suggests, it goes from a smooth flyer to a flying squirrel pretty quickly!

Larry

hey larry,

thanks for the reply. yeah i'm measuring as close to the fuselage as i can get. i'm thinking of moving the reciever right below the main landing gear. i also read that you could move the engine further up on the mount but, wouldn't that look pretty weird sticking so far out of the cowling? what about spinner weights? or do you think i should just go with 4 3/4 cg? thanks again

one more ? . how did you come up with 4 3/4 cg? okay 2 more. where did you mount all of your eqipment?

I think I had both the battery and the receiver in front of the servo tray up as far forward as they would go. The servos were Futaba 9001, which are fairly light. I also had an aluminum spinner nut, not weighted. The remote glow and Dubro fueler would have added a little to the nose weight, but not over an ounce.

Larry

You can mount the battery up under the fuel tank for more weight up front if its not up that far already.

Larry, I think by the time you add the muffler and a heavier prop to the 52 there may be more than 2 oz difference.

Ed M.

Ed,

Good point. The 52 muffler is fairly light, but I used an APC 11x7 prop. That's not a lightweight.

Larry

I've had two engines in mine; a Saito 72 four stroke and the current engine which is an OS50SX. I have a 1600ma NIMH battery in the compartment under the fuel tank. With the Saito I originally had a couple of ounces in the nose to keep the Cg toward the front of the range. I eventually removed the weight as I gained confidence in the plane and allowed the Cg to go back near the rear limit. It's more toward the middle of the range now with the heavier 2-stroke and no added weight.

Key for me was putting the battery under the fuel tank.

Greg

hey gs,
thanks for the reply. i would like to put the battery under the fuel tank but it is to big to fit into that compartment. i would like to have to not buy another battery. any other suggestions would be great.

What size battery pack are you running? I just looked and it would be real easy to fit a sub C 5 cell pack up there with no problem. Thats up to 3600 mah and some erious weight. All it takes is any flat pack.

Ed M.

hey ed,

the only problem is that the battery pack i have is square. well i guess i have to go get another one. how did you secure it? zip ties?

thanks man

Wrapped in foam to fill the void space and its stays in place all on its on.

Ed M.

Go with the flat pack so you can put it way up front, then if you need to you will also be able to put your rec. a little farther forward. Then if it still isn't enough move the engine out a bit. You will be surprised that just moving the engine a little will make a lot of difference. What ever you do TRY to not add any more weight. That said if all else fails buy a heavy prop nut. The 40la is no power house but if you keep the weight down it should do OK. ENJOY !!! RED

hey red,

i'm gonna go pick up another battery and move some stuff around. how big of a prop nut? if i move the engine up, would it look kinda wierd sticking out of the cowling? if all else fails, i'll move it up.
thanks for the info, casey

Mine was tail heavy as well. Here's my thread on the issue this spring:

[link=http://www.rcuniverse.com/forum/m_2794931/anchors_2794931/mpage_1/key_/anchor/tm.htm#2794931]http://www.rcuniverse.com/forum/m_2794931/anchors_2794931/mpage_1/key_/anchor/tm.htm#2794931[/link]

-tychoc

I have a Venus 40 with an OS46AX. With a 1500 mAhr NiMh battery forward under the fuel tank
and the receiver in front of the servos the plane balanced just forward of 4-5/8" (about 4-3/8")
per the manual. The plane was built per the plans and with the included hardware and came in at 5.6 pounds. I think I have the engine slightly forward from the instructions as the gap to the between the spinner and the cowell is about 3/16" of an inch. This may have helped, but even so it's very curious why some come out so tail heavy, and others balance fine.


I really like this plane. To bad they don't also make a 60 size of about 61" wing span as I have a 20 year old OSMAX 61 FSR ABC that needs a good home.

Amen, I'd like to put my OS 91 FS on something like that.

I had an OS 70 on my Venus 40. I'm afraid I never checked the weight, but I ended up adding and ounce or two to the tail. Sure was a sweet flying model.