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Sep 09, 2012, 07:08 PM
A trail of smoke is GOOD!
waynemia's Avatar
Build Log

Flying Foam's Mothership EP

I received an 83" WS Mothership from Flying Foam on Saturday.

Here is a link to the kit:

I have built two wings from trick r/c.

I have also built a homemade wing wire-cut from foam insulation board.

This kit leaves a few things to the builder. They don't have anything for a motor mount and there are no cut outs for batteries, ESC, rx, or servos. The motor mount maybe the most challenging to build. I plan to build this as a pusher design.

The motor will be a Turnigy G46 and a 60A ESC. I want to be able to fly both 4S and 5S so the battery compartment will have to allow for either.

I will start the build soon and plan to document it here. I would also like any collaboration from people here on RCG. I have searched some and I don't see a lot about this kit.

Any input would be helpful. My basic plan is to build it similar to a Zagi. I also have a Zijji I can use to model.

The first improvement will be to add a horizontal spar on the CG. The kit has four CF spars but it does not have a CG spar. Most of the assembly will be epoxy or 3M 77 glue. I am not sure about hinges. I normally use hinge tape on wings but these are a bit larger and I may use an alternate method.

The kit also uses coroplast winglets. I may change those to ply or poly before assembly.

I would like to hear from anyone with experience with this kit in a pusher configuration. Pictures/videos/links would be great.

Last edited by waynemia; Sep 09, 2012 at 07:24 PM.
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Sep 10, 2012, 03:34 PM
A trail of smoke is GOOD!
waynemia's Avatar
Here is a picture of the foam cores in the beds. The yellow ruler is 4'.
Sep 10, 2012, 07:16 PM
Foam Guy
Originally Posted by waynemia View Post
This kit leaves a few things to the builder...
Let's be honest Wayne. We leave a lot to the builder with the EP version of the Mother Ship. You are the first person to power this thing since I took over FlyingFoam from Bob. I'll help out as much as I can...

Not sure about your requirement for a spar at the CG. The current spars are close to the aerodynamic center (c/4) so will do what they need to do under normal flight loads. I think you are right that it needs a fifth spar, but I don't think it needs to be at the CG. Could be, but does not need to be. Mostly needs to form a triangle with the other four to provide more torsional rigidity at speed and under motor/prop torque. I do not like flat spars in EPP airfoils as EPP tends to twist no matter how much tape and CF you put in it, so I prefer tubes. Not as stiff as flats when flats stay vertical like they should, but they don't seem to in EPP airfoils anyway. A small tube under your motor mount (or there about) running out towards the tips at a 90 to the root chords should help.

[Edit] 5th spar right about where you have the yellow ruler is what I am trying to say. [Edit]

Last edited by cglusky; Sep 11, 2012 at 07:43 AM. Reason: Adding
Sep 10, 2012, 07:41 PM
A trail of smoke is GOOD!
waynemia's Avatar
Thanks Coby. I will document my little journey and maybe help others down the line. I don't know why it is black. It is a little coarser than other epp planes I have worked with. I don't think it will matter except for maybe the colored tape.

The spar I am referring to would be a ply spar placed vertically in the foam across the mid seam and probably at the CG. I think it will nicely prevent flexing along the center line during flight.

The battery box may be cut all the way through the plane. A poly floor could then be added on the bottom. I will need a top cover and I will try to fabricate something light with ventilation for the batteries.

The main issue now, not a problem, is a table big enough to work on it. I will have to clear an 8' table. That is a good thing.
Sep 11, 2012, 07:50 AM
Foam Guy
Black EPP tends to be just a hair stiffer then white, so we prefer it for our flying wings.
Sep 11, 2012, 01:01 PM
Registered User
As a long time lurker and someone who doesn't fly any more I just wanted to chime in and say how wonderful it is that this kit is still being offered. I have always wanted one of these and lusted after a mothership when I had the time but no space for it. Now, I have the space and I suppose I have the time... hmm. Please link the shop where you bought the kit. Anyway, I look forward to your efforts to get this off the ground.

If I were to do it, I would prop it for maximum thrust and perhaps 40-50 MPH. I think that choosing thrust over speed will will let you ascend easily do you can do what the wing does best: glide and swoop. Thats what I would do anyway. For a motor mount, I would look at the style offered by Its an aluminum bracket in the shape of an 'L' and then make your own. Anyway, I wish you luck with your build and will be watching.
Sep 11, 2012, 01:05 PM
Registered User

keep up the news please

I have given a lot of thought to building the 'Mothership' also.

Now that they have moved/changed hands to Colorado I may make this a winter project.

Will be watching these posts and looking forward to what you figure out.

I kinda liked that there were no cut outs - lets ya do it your way.
Sep 11, 2012, 03:09 PM
A trail of smoke is GOOD!
waynemia's Avatar
Thanks Nutty, the link is in the first post. Click on Mothership and here it is again in the long form.

I looked at the justgofly. The mounts they have don't look like they will work the way I want. I will keep it in mind as I start.

KB5IXD - I am KB5UQ although not active anymore.

Coby has been nice and said he cut a couple extras when he did mine so it is a good time to order. Some people like to roll their own and some don't. It just makes it faster to get to the flying which is what I am after. I am competent as a builder, it just takes longer.

I have a couple of projects in works so It will take a week or two to get into full swing on this one. I hope everyone is patient and chimes in on the build.
Sep 15, 2012, 12:43 AM
Registered User

MotherShip Background Info

As founder of FlyingFoam and the creator of the MotherShip, I thought I would provide some background information about this large flying wing.

I created the MotherShip in the late 90's when slope combat was going crazy in Southern California. FlyingFoam was created later, but at the time I was hand cutting the Cheap Shot, a 48" span flying wing that used the same planform as the Zagi and Boomerang, 2 very popular flying wing designs at the time.

The Cheap shot was a refinement of the Boomerang, using thicker airfoils, large elevons and a lot of tip washout. This combination resulted in an airplane that had superior recovery characteristics and resulted in a number of wins at local slope combat contests by my son and a couple of his friends. The rules for slope combat were pretty simple. Get into a collision with another airplane and recover without hitting the ground. To prove you still had control, you had to do a roll, and if the other plane couldn't recover, you got credit for a "kill". The most kills wins!

Recovery characteristics were everything and speed and efficiency didn't mean much, but it took a while for the other designers to figure that out.

The idea for the MotherShip came about at a combat contest in Laguna Nigel, CA in 1998. One of the flyers had a 60" span wing that used thin airfoils, and no washout. It was a tip stalling nightmare, but due to it's size, it was real tough to knock down. I made some calculations and came up with the 83" span MotherShip, which was the largest I could go using the 24" x 48" EPS foam sheets that I was buying at the time. The MotherShip is a scaled up Cheap Shot using the same airfoils, planform and other design features, all scaled up to an 83" span.

The first outing of the MotherShip at the local slope proved it was a devastating combat killer, as the normal sized airplanes would simply bounce off of it. It was so good that one flyer landed his plane and declared that he would continue flying when I was done! After the word got out, all future contests had wingspan limits of 48" or 50", so the MotherShip became a novelty. I used the concept of a larger and heavier plane to create the Wide Glide which was a 48" span flying wing with a wider chord both root and tip, thick airfoils and huge elevons. With a 22 oz flying weight, it faired better in a collision and still had great recovery characteristics. The Wide Glide continued to win a lot of Southern California combat contests.

After creating FlyingFoam in January of 2001, I sold quite a few MotherShip kits. The original design utilized 2# EPS foam with an EPP leading edge and no spars. A few years later I began selling all-EPP Motherships cut from 1.3# EPP and using top and bottom 1/4" diameter tube spars that sweep with the wing. Later the powered version was added to the product line as and all-EPP design, but with no washout. The washout worked great on the slopes, but caused instability or a waggle exiting a turn due to the higher speeds of the powered version. Eliminating washout solved that problem and all powered versions are cut with no washout.

The other problem that reared itís ugly head with the powered version was a lack of torsional stiffness in the wing tips. A tight covering job and a 5th spar placed as far aft as possible solved that and helped reinforce the motor mount area for the pusher configurations. The reason the 5th spar isn't included in the kit is a simple one. It won't fit in the box! A larger box would greatly increase shipping costs, so it has been left out.

The MotherShip has been flown in many configurations, in both tractor and pusher designs, and with cameras for FPV and aerial surveillance. As a result, I never included a motor mount or pockets for batteries and electronics.

I have been amazed at how the MotherShip has stood the test of time. It has been around for 14 years and I'm sure Coby will continue to produce the kit as long as there is demand.

I will keep an eye on this thread and try to answer any questions you may have.

Enjoy your MotherShip!

Bob Mellen / Retired former owner of FlyingFoam
Sep 15, 2012, 04:54 AM
resU deretsigeR
PaulVi's Avatar
Nice history write up Bob Thanks much for the great background..
Sep 15, 2012, 08:18 AM
A trail of smoke is GOOD!
waynemia's Avatar
Thanks Bob. I have been toying with cutting a giant foam wing since I got my first Zagi. A friend had a small, 32", homemade wing. I helped him wire cut some of those cores and built one. My friend and I have been doing friendly combat. It is pretty hard to make contact with just a couple of planes in the air.

I am trying to clear a couple of other projects so I can have room to start the MS. I am still toying with some motor mount design ideas. I want to do a pusher. I find the the pusher has a clear forward view for cameras and saves the motor in the event of a crash. I am now flying the homemade wing and a Zijji - the Trick RC wing set up for brushless inrunner. Trick RC moved the motor mounts forward, closer to the CG. This creates a need to cut out some of the back for prop clearance. The Zagi has the prop n the elevon area.

My plan is to glue the two wing halves together, tape the elevons, and winglets in place, and then lay the rest of the components on the wing and try to come up a layout and mount design.

I hope to get started next week if I keep making progress on my current projects.

One question Bob. When I mount my pusher, an outrunner, should the motor thrust line be parallel and above the cord line. My plan was to imitate the Zijji but I may as well pick your brain.

Sep 15, 2012, 09:56 PM
Registered User

Pusher setup

I'm not a fan of pusher setups, but most builders set them up this way. It is more difficult to construct a motor mount, and balancing can be tougher, but if camera view is the issue, then pusher is the way to go.

I built several MotherShips as pushers. I found that they will climb under power with a zero thrust setup. Placing the motor center line above the wing will help, but some down thrust will also be needed. About 2 degrees is a good place to start, and the aft end of the motor shaft should be lower than the forward end to get down thrust. This helps to push the nose down under power, but you will probably still end up messing with the trim. I never could get it perfect.

Anyway, once you get it in the air, you will find it is far more stable than normal size flying wings. The roll rate is slow, but you would expect that from a big wing.

One last warning. Don't try flying it with a tail heavy CG. It should balance at 14 1/4" from the nose. You can go back as far as 14 1/2", but any further than that and you will have a disaster on you hands! If you have to add nose ballast, do it!

Enjoy, Bob
Sep 15, 2012, 11:40 PM
resU deretsigeR
PaulVi's Avatar
Making a motor mount is not all that hard. start with a thin ridged plate of aluminum and use 2 pieces of aluminum angle (iron) clamp the plate with the angle and mount the motor to the angle it works well the motor will hang out the back more or you will have to cut the motor mount in further but it works well and is simple enough to make with hand tools and hardware store matirials

just cut a slit in the foam on the angle you want the motor on and you should be good to go..

Thos is a nother way to do it as well it worked great and kept the motor father foward
Sep 17, 2012, 02:40 PM
Gasbags & Gussets
jswain's Avatar

another motor mount

Additionally to Paul's suggestion, Windrider makes a pre-fab motor mount with mounting plate and matching backplate for pusher configuration.

here is the web link ->

unfortunately i just started reading this build blog.... and it cost me some $$'s for a new MS flying wing kit..... that said i get to do the happy dance again when the big brown truck comes with a new box.

This model will be perfect for the moderate winds and semi-rough ground at a local slope soaring flying site in riverside, ca. As a bonus, Gary G. shouldn't be able to knock me out of the sky with his combat wings

Last edited by jswain; Sep 17, 2012 at 02:52 PM. Reason: web link fixed
Sep 17, 2012, 07:49 PM
A trail of smoke is GOOD!
waynemia's Avatar
Thanks for the links. I plan to incorporate the motor mount with a lateral spar. I was looking at the plane last night and discussing with a friend and I think I have a good plan that will eliminate flex along the center line.

Thanks for the information Bob. I prefer the pusher as there is less opportunity to damage the motor and the clear view ahead. I have experienced the climb with power issue and can mix that out with down elevator mixed to the throttle. It takes a couple of test flights but I can get 90% of the pitch on throttle out that way.

I have a couple of other projects this week but hope to start by next week.

Congrats JS. I am looking forward to the first flights on this one.

Here is a video of my Zijji flying from this weekend.

Trick RC Zijji Flying Wing On-board Video (11 min 13 sec)

This video is of the smaller homemade wing we wire cut from Lowe's Foam.

bwing1_0002.wmv (2 min 16 sec)

Thanks again for your participation.

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