Author Topic: battery mounted on wing? (Read 1466 times)

Electric George · « **on:** February 09, 2021, 10:17:48 AM »

I am building a profile fuselage Sig Banshee and having got to the point where I can tape the components together to check the balance. I have discovered that it is too nose heavy. I was expecting to have to shorten the nose and had hoped the battery would fit between the L.E. and the motor, at an angle, on the outside of the fuselage.
However with it would mean adding approx 4 ounces to the tail to get the balance and works out as approx 44 ounces in total for the airframe.
I have worked out that I could shorten the nose 4" and mount the lipo on the top of the wing at the canopy location and would not have to add weight.
Would this work? Or would it affect the flying of the plane?
I am only wanting to use it as a basic stunt trainer.
Thanks all.

Brent Williams · « **Reply #1 on:** February 09, 2021, 10:39:00 AM »

Move the wing forward 2 or so inches. It will be beneficial to the airplane performance in more ways than just fixing the CG.

John Rist · « **Reply #2 on:** February 09, 2021, 12:59:26 PM »

On this BB is a discussion on converting a Ringmaster to electric. https://stunthanger.com/smf/gettin-all-amp'ed-up!/electrified-ringmaster-s-1/ It may give you some ideals on how-to.

Fore sure it doesn't matter if you mount the lipo on the top of the wing at the canopy location. To reduce drag it would be nice if you can bury it somewhat in the wing.

PS I have an electric Ringmaster with the battery berried in the wing. It came out tail heave. Had to add noise weight. See:

https://stunthanger.com/smf/gettin-all-amp'ed-up!/e-ringmaster-as-built-by-tom's-building-service/

Dennis Toth · « **Reply #3 on:** February 09, 2021, 01:24:42 PM »

EG,
What setup are you using for the Banshee? The Banshee is not that big and can likely use a 2814 size motor 2820 at most with a 2200 mah battery pack. This should be a power package weight of around 11oz similar to a muffled Fox 35 with 4oz of fuel. I did the Ringmaster conversion and you can cut a pocket into the bottom of the outboard wing center planking then add a 1/8 lite ply plate with Velcro straps. If you do this make sure you add some additional sheer bracing along the main spare. I think the Banshee fuse is deep enough so you won't have to cut into the leading edge. The battery plate should be mounted on some 1/4 x1/4" rails. I added a half rib on top of the plate to lock it top and bottom. I would test balance the ship and extend the plate over the end of the LE to allow adding a strip on the near the end. On my Ringmaster I found that about 1/3 of the battery had to extend over the LE to get the balance correct.

Best, DennisT

MikeyPratt · « **Reply #4 on:** February 09, 2021, 01:56:07 PM »

Hi George,
At minimum, move the wing cut out in the fuselage forward at least 1-1/2”, or 1-3/4” just to make sure. Increase the span of the stab & elevators 4” and make the Fin & Rudder out of 3/16” Balsa. No need for an ugly box sticking out of the wing. Use a front motor mount so as not to loose battery mounting area in the nose. I’ve built 4 of them now and they all balanced where I wanted them to. If you want I can make a few drawings for you, but it’s really that simple to do.

Later,
Mikey

Electric George · « **Reply #5 on:** February 10, 2021, 02:59:14 AM »

Hi all,
Thanks to everyone for the replies. They all contribute to my working out which path I should take.

The power system is : Emax 2820/07, ZTW 40amp esc, KR Timer, 4s 2200ma lipo, 11x5.5 prop. Weight on my scales (not including prop) is 11.26 ounces (so you are bang on, Dennis).

Summing up it Looks like I have two options: 1. My thanks to John Rist -Shorten the nose and mount lipo on wing alongside the canopy- it aint pretty but it will work ok for basic stunt training.
2. My thanks to Brent and Mikey - move wing forward, move undercarriage forward also? Add 4" to stab/elevator span, try the balance again.

I shall also look into the suggestions for half in /out the wing mounting.

Now I have to balance up the fact that I was looking for a simple project as the model will possibly not last long in my inexperienced hands against the extra effort that will create a better looking and flying aircraft.

Plenty for me to ponder. My thanks again to you all.

Dennis Toth · « **Reply #6 on:** February 10, 2021, 07:31:25 AM »

George,

Update: Just was looking the the list you setup and found a SIG Banshee Conversion on pg 4 by Don Coe , Nov 30, 2014 that shows the battery box on the top of the wing next to the canopy might do what you need.

One other thing to keep in mind is positioning and securing the ESC and timer. If you look at the E S1 Ringmaster thread you can see I inset them into the fuse, securing them with industrial strength Velcro in the pockets. I have used this on other ships and it works well. It allows you to keep the wiring neat and pretty. On the CG don't ignore the weight of the finish on the back parts of the ship, it can be a lot more weight than you might think. I did one ship and taped everything in the approximate location to get the balance before cover and finish think it would be close. Turned out off by a couple inches and I had to add an extension to get the battery further forward.

How far along are you in the build? Is the wing center planking complete? For me I like adding the extra area to the stab/elevator but not repositioning the wing. I have done this mod to a Tutor II and actually shorten the tail moment by an inch. For the Banshee I would expect a hinge to hinge measurement of around 14 - 15" kinda in line with Nobler numbers. One simple option is to move the stab back a bit 3/8 to 1/2" or so. Since this is something you will use to perfect your pattern I would not throw out the whole fuse, make it look neat but the Banshee has won its share just as is.

Best, DennisT

Electric George · « **Reply #7 on:** February 10, 2021, 10:48:37 AM »

Hi Dennis,
Thanks for your further input.
I read through your thread and picked up some good ideas, thanks. I looked at the idea of placing the battery below the wing and it will fit there. I need to look at how I will secure it. If I have enough space to get decent velcro straps and a strip of velcro on the lipo and fuse (like my R/C 3d planes) then it would look prettier compared to above the wing and with a box like the Don Coe idea. It is still not on the center line which I was concerned about. However, it seems that apart from the ugliness it does not have too great an impact on the flight performance and so it is a good solution for me as a beginner.
The flap hinge to stab hinge is 14". I tried moving the stab back an inch on the fuse but it resulted only in an inch movement of the lipo and so not enough to get it off the wing.
Unfortunately, having weighed the power system and compared to a fox 35 estimated that it would work out ok but decided that I needed to get the airframe as close to complete to get a true picture. I have covered the rear of the fuse leaving only the nose so that I could reduce the length. Wings complete and covered. Tail plane complete and covered. All pushrods taped in place including ball joints etc. Built as stock and covered in film.

John Rist · « **Reply #8 on:** February 10, 2021, 11:46:30 AM »

Quote from: Electric George on February 10, 2021, 10:48:37 AM

Hi Dennis,
Thanks for your further input.
I read through your thread and picked up some good ideas, thanks. I looked at the idea of placing the battery below the wing and it will fit there. I need to look at how I will secure it. If I have enough space to get decent velcro straps and a strip of velcro on the lipo and fuse (like my R/C 3d planes) then it would look prettier compared to above the wing and with a box like the Don Coe idea. It is still not on the center line which I was concerned about. However, it seems that apart from the ugliness it does not have too great an impact on the flight performance and so it is a good solution for me as a beginner.
The flap hinge to stab hinge is 14". I tried moving the stab back an inch on the fuse but it resulted only in an inch movement of the lipo and so not enough to get it off the wing.
Unfortunately, having weighed the power system and compared to a fox 35 estimated that it would work out ok but decided that I needed to get the airframe as close to complete to get a true picture. I have covered the rear of the fuse leaving only the nose so that I could reduce the length. Wings complete and covered. Tail plane complete and covered. All pushrods taped in place including ball joints etc. Built as stock and covered in film.

Would love some pictures.

Ken Culbertson · « **Reply #9 on:** February 10, 2021, 03:10:48 PM »

Quote from: Electric George on February 09, 2021, 10:17:48 AM

I am building a profile fuselage Sig Banshee and having got to the point where I can tape the components together to check the balance. I have discovered that it is too nose heavy. I was expecting to have to shorten the nose and had hoped the battery would fit between the L.E. and the motor, at an angle, on the outside of the fuselage.
However with it would mean adding approx 4 ounces to the tail to get the balance and works out as approx 44 ounces in total for the airframe.
I have worked out that I could shorten the nose 4" and mount the lipo on the top of the wing at the canopy location and would not have to add weight.
Would this work? Or would it affect the flying of the plane?
I am only wanting to use it as a basic stunt trainer.
Thanks all.

The Twister and Banshee are very similar. I was able to properly balance my twister by putting the battery on one side of the nose and all the junk on the other. Didn't have to cut the wing. There are some rather short, and for that matter light 4s batteries that should fit fine.

Ken

MikeyPratt · « **Reply #10 on:** February 10, 2021, 03:20:20 PM »

EG,
I’ll send you a few drawing as soon as I can so you get the total idea. The C.G. Should be .5 to .75 ahead of the stuck balance point. It will fly very well at that C.G. Position.

Mikey

Electric George · « **Reply #11 on:** February 11, 2021, 02:14:35 AM »

Thanks again all for the thoughts and suggestions.
John - I will see if I can sort out some pics later.
Motorman - Very useful to read your comments as someone who has built and flown the Banshee. Your comments regarding the battery on the wing has me swinging back to option 2. Regarding going i.c. I confess I have already considered this! However, In an effort to keep things light and as is usual for my R/C electrics, I glued the bearers/ doublers with a good quality Aliphatic. I have no doubts over the structural integrity for an electric set up but do not know if it would hold up to the high vibration levels of an i.c? I have 3 lipos but can also field charge and so not so not really a problem
Ken - I already have the esc/etc taped to the opposite side of the lipo. I will have a look into what minimum capacity I could get away with.
Mickey- That is very kind and would be very useful. I am swinging back to the idea of moving the wing etc.
Thanks again all. I will ponder some more.

Electric George · « **Reply #12 on:** February 11, 2021, 07:39:11 AM »

Some pics: 1. shows the airframe taped together to get an idea of c of g.
2.shows the motor and esc taped in position to get the balance needed - on the front of the lower wing spar.
3. shows the lipo position under the wing.

Electric George · « **Reply #13 on:** February 11, 2021, 07:48:50 AM »

Out of Curiosity:
I taped a Fox 35 to the nose and 3 ounces of weight to represent a fuel tank. Balance point came out about the same position.

Ken Culbertson · « **Reply #14 on:** February 11, 2021, 07:58:00 AM »

Quote from: Electric George on February 11, 2021, 02:14:35 AM

Ken - I already have the esc/etc taped to the opposite side of the lipo. I will have a look into what minimum capacity I could get away with.

I flew mine for 2 years with a Cobra 2820/12 using 4s 2200's. Fancherized,48oz, CG 1 1/2" behind the LE. The nose on a Banshee is a bit longer than the Twister.
Good luck! - Ken

Dennis Toth · « **Reply #15 on:** February 11, 2021, 08:05:34 AM »

George,
Since you have the fuse 90% done and you seem to have approximated equipment locations to get the CG, I would not spend time building a new fuse. Since you can get the battery under the wing I wound build a little wedge to support a 1/8" lite ply plate that glues to the center planking. Cut slots for two Velcro straps and put a piece on the plate and bottom of the battery to hold it. Cut away the covering to attach the plate and wedge to the planking and use epoxy to attach it. I would mount the ESC and Timer on the outside of the fuse nose rather then under the inside wing, just for looks. Good luck keep us informed what you decide.

Best, DennisT

Ken Culbertson · « **Reply #16 on:** February 11, 2021, 10:41:02 AM »

I just reread the thread and, although I may have missed it, it appears that we all left out one very important question for you. Are you trying to hit the CG on the plans? For whatever reason, and I can't explain why either, electrics balance considerably forward of where the same plane would balance with an IC. With nothing under the wing I added 2 ounces of nose weight when using a 2200mh battery. After a while I found some similar 2800's that balanced it out. Nice thing about electrics and nose weight. If you can't move the battery forward you can always get a bigger one. That way the weight you add has legs!

Ken

Electric George · « **Reply #17 on:** February 12, 2021, 02:30:29 AM »

Hi Dennis,
Thanks. It is very kind of you to take the time to provide the sketch. I have a clear idea now of how I will go about it but I just need to decide whether or not to go the other option and move the wings forward etc.
There is no rush and so I can ponder the options for a few days.
Thanks again.

Electric George · « **Reply #18 on:** February 12, 2021, 02:35:05 AM »

Quote from: Ken Culbertson on February 11, 2021, 10:41:02 AM

I just reread the thread and, although I may have missed it, it appears that we all left out one very important question for you. Are you trying to hit the CG on the plans? For whatever reason, and I can't explain why either, electrics balance considerably forward of where the same plane would balance with an IC. With nothing under the wing I added 2 ounces of nose weight when using a 2200mh battery. After a while I found some similar 2800's that balanced it out. Nice thing about electrics and nose weight. If you can't move the battery forward you can always get a bigger one. That way the weight you add has legs!

Ken

That's a good point, Ken. I assumed that an electric set up would only result in a small movement forward in terms of C of g and so not enough that I shouldn't aim for the original spot and make adjustments from there. 2 ounces sounds like a lot, though.

MikeyPratt · « **Reply #19 on:** February 14, 2021, 10:16:02 AM »

Hi E/G,
The more I look at this the more I’m convinced that you can go two different directions,

(1). Build the model as is and use you Fox 35 to power it. This will allow you learn the basic maneuvers needed to fly a complete patter, mostly you need the handle time. The Banshee and the Twister are more that fan Awesome job to do that, or build a stunt trainer like the skyway 35 with a OS 20 FP or 25 LA.

(2). As your Banshee stands right now you only need to change a few things to convert it to electric power, move the wing forward 1-3/4” and increase the size of the stab & elevators and build a an electric motor mount. As soon as I finish the drawings for it I’ll post it here.

Just so you know, I do know what I talking about, I worked at SIg Manufacturing for more than 20 years as a designer and Production Engineer and built many copies of the Banshee and Twister and many different R/C models.

Later,
Mike Pratt (Mikey).

Electric George · « **Reply #20 on:** February 15, 2021, 12:45:04 AM »

Hi Mikey,

Thanks for the reply and your thoughts on this which are very helpful.
I look forward to the drawings which will be great for me and I guess many others who find themselves pondering an electric conversion of the Banshee.
I 'll take a break from the build for a few days and make a Stooge ready for when Covid/weather allows some flying opportunities.

Thanks again,
George

Brent Williams · « **Reply #21 on:** February 15, 2021, 03:26:19 PM »

Here is a drawing showing the stock Banshee fuselage (top) and a modified Banshee with the wing moved forward 1.5" (bottom). It will result in a much better flying airplane than the stock version. It really should be implemented on your build.

Brodak's profile conversion package is inexpensive and include a cavity for the battery. https://brodak.com/electric-accessories-1/conversion-kits/universal-d-electric-conversion-for-large-profile-models.html

The 3D Printed motor mounts from Okie Air are a very clever solution. https://okieair.com/shop/ols/products/printed-motor-mount

Bob Hunt's HardNose method is very clean. https://stunthanger.com/smf/gettin-all-amp'ed-up!/nose-construction-for-rd-1e/msg390207/#msg390207

Pat Johnston has a simple rear mount conversion package drawing you could copy. https://stunthanger.com/smf/gettin-all-amp'ed-up!/three-conversion-kits-for-profiles/msg476678/#msg476678

Electric George · « **Reply #22 on:** February 16, 2021, 04:18:32 AM »

Hi Bret,
Thanks for the drawing and your thoughts which are very useful. It is good that there is no need to move the undercarriage legs forward. It looks straightforward - I just fill in the cut out then cut out again forward of the original position.

The links are great and I will look them over. Unfortunately I live in the UK and so am unable to get hold of the many kits and accessories you have available. I can't even get balsa at the moment although I am hoping that will change soon.
I am thinking I will spend the extra time moving the wing forward and increasing the tail size as suggested and save it as a next step after using something else to learn to stunt/ crash!
Thanks again,
George

MikeyPratt · « **Reply #23 on:** February 16, 2021, 11:42:52 AM »

Thanks Brent,
I’ve cant find my drawings on the electric Banshee. Thanks You for posting them.

Mikey