VTO free flight model

A large number of free flight designs convert to RC very well. Just something to think about.

Phil

I can see this is going to be an unusual build and can't wait to see the finished article.

From the plans (or what I can see!) - it looks like the engine will have a propeller front and back behind the tank and the engine unit(including tank) will spin around with the rear propeller. That isn't going to be easy.

From that (if I am right) - I assume that this will be vertical take off and then float back down in the same attitude.

This will be a very novel plane.

Yes, I like what your doing! This is an election year, so there will be plenty of building material like that available before and just after the elections! Can't tell from the pictures are you using 2mm or 4mm plastic sign material?  I think the "spinning nose" of the engine assembly will let this one fly very similar to the "flying rags" of my youth....with a bit more stability and just as much fun!  Keep us posted of your progress and flights.

Hi Guys, thanks for your coments. I got a 049 reed engine with a stunt tank. That way, I don't have to extend the filling tube to keep the fuel inside the tank when mounted vertically. It will certainly take off vertically but I don't know if it will continue to climb that way. The article says it flies and land "horizontally" but it will be a fast landing I guess. I used 2,5 mm coroplast but for the fins, I will use 3 mm. I have some left overs from my other planes.

Lieven

A few pictures of my progress on the plane. I cut out both tail pièces with a key to fit into slots on both sides of the fuse. At each fin extremity, some hard balsa was inserted and glued in the corresponding flute. I started making the nose block of 7 sheets of 5mm balsa.

Coming together Nicely , good to see you have not abandoned the project cant wait to see it in the air . getback

Very cool build!

Fantastic project Overlord.
I want to build someday the famous american V.tol motorglider Satellite, also 1/2 A with Tee dee.

Thanks guys. Glad you like it.

I had a look at the engine I will use on the plane. It's an engine I bought from Robot 797.

https://www.coxengineforum.com/t8621-cox-baby-bee

I removed the muffler and replaced the gaskets. I also replaced the pick up tube and wedged it well against the backplate so the engine could empty the complete tank. The engine has a nr6 cylinder: 2 bypass ports and no SPI. The reed is the conventional copper star reed and I mounted a standard head.

I tested the engine running vertical. In that position, the tank can hold 3,5 to 4 ml of fuel before it squirts out of the other tube. With that quantity, the engine runs about 35 seconds. I recorded a run with 2 ml of fuel which gave a run of about 20 seconds and a run with 1 ml of fuel giving about 14 seconds of running time. With only 1 ml of fuel in the tank, the engine was more difficult to start.


https://www.youtube.com/watch?v=ozzhNasDr5A

Lieven

Lieven why are you using a 8cc tank if your only using 1-2 ml of fuel , if it were me I would but a BB tank on it if you have one , or maybe I am wrong again and it want run vertical ? You could put a hose from filler tube around the bottom to the other and cut a slot (opening) in it at the bottom I hear that will cure inverted flight with the Bee . I am thinking of the weight only if it matters , but it did sound good ! getback

Looks like this plane design was inspired by the 50's Convair XFY-1 "Pogo". Good luck with it.

George

getback wrote:Lieven why are you using a 8cc tank if your only using 1-2 ml of fuel , if it were me I would but a BB tank on it if you have one , or maybe I am wrong again and it want run vertical ? You could put a hose from filler tube around the bottom to the other and cut a slot (opening) in it at the bottom I hear that will cure inverted flight with the Bee . I am thinking of the weight only if it matters , but it did sound good ! getback

Hi Eric, I've been thinking about what tank to use and weight and all that. The stunt tank is the best option I think: It keeps fuel inside without the need to add extras to the engine- tank assembly.

Other options are:

1) Babe Bee tank and back plate. Two tubes have to be added to keep fuel in the tank. Difficult to do IMO as both filling nipples are rather small and tapered. Glue them on?? and make some sort of a retainer to keep the tubes in place and solid enough so that nothing flies off while the engine is rotating.

2) Babe Bee tank with a stunt tank back plate: no need to add extra tubes but a hole needs to be drilled in the curved part of the tank for filling and venting. This would also give a difference in diameter in the inlet tube as the back plate has a 2mm hole in way of the venturi but the tank inlet pipe has only a diameter of 1mm and centimes.

3) Product engine back plate. This means that an external tank has to be added and well fixed. Not the most beautiful option. Some helicopter plans on Outerzone show the fueltank in the fuse and fuel passing through the pivot. That looks maybe easy on paper but not so easy to make.

I don't think there is  a big difference in weight between the 5 and 8 cc tanks. What could be improved with a shorter tank is the CG position.

I have a few questions:

Does someone know the weight of a OK Cub 049 with tank?

On the Cox Comanche, Cobra and Sky jumper, is the engine mounted in the centre of the pivot? The back plate that Bernie sells seems to have an engine offset mounting plate. Is that to better balance the rotating engine?

http://coxengines.ca/cox-.049-engine-firewall-helicopter-mount.html

The Sky Copter doesn't seem to have any weight to balance the pivot. I never had one in my hands. With the engine running and turning around, does it wobble a lot when holding?

George, Yes indeed. the VTOL projects were popular in the 50's: No need for a runway but difficult to land without a rear view mirror. Lockheed and Convair are well known. In France, there was the SNECMA Coléoptère:


https://www.youtube.com/watch?v=AixAp_MgGVo

This could bee an option too:



A helicopter version of the product engine as seen on Cox free-flight helicopters. Straight-forward, but maybe a little boring way to go

Image "borrowed" from http://www.mh-aerotools.de/airfoils/cox_productengines.htm

You could also extend the stunt-tank's pipes with a fuel hose tied somehow in a way that the ends point up. Eric's idea could be useful too, or you could just take a 2-pipe backplate and run hoses from it's pipes up to the level of the crankcase. Maybe use an exhaust deflector with the "deflectin' part" pointing to the side or the bottom of the engine for a quick'n'easy bracket to tie the hoses to?

Kari, Thanks for hurting your brains. That's indeed the standard cox free flight heli engine with the purpose built backplate. It looks unusable for the creative modeller with that plastic tube at the back. It needs to be bolted on the backplate support that Bernie sells. Imagine what will happen when the plane lands with the fuel tank down. It can olso land with the cylinder down, because heavier. I don't like it and besides, I haven't got one of them.

What you said about the pick up tube is what I was trying to say in point 1 in my previous post. Only I couldn't find the proper words and you explained it the right way!

I'm almost finished making the parts for the pivot.

Wonder if one of these would work ? and I have a BB 5cc tank that has been drilled , I have never ran either . If you use the small silicone tubing it should stay put ( the stuff for TD engine has a really good grip! Eric

Lieven, as you probably know, giving unsolicited advice about stuff I don't really know is one of my fortes (After all, I AM an engineer )

I don't know how your plane is supposed to fly, will it eventually turn into horizontal flight, and what exactly happens when or after the engine stops, and which end will hit the ground first

The chopper engine certainly is not the most attractive unit, but I think one could remove the choke pipe and then it would install like an ordinary horseshoe engine. The tanks were sold at one time by one of the usual suspects, not sure if they are available now.

Yes, it seems I missed the point in your previous message, sorry

I was inspecting one of the recent arrivals to my sanctuary of homeless bees, and just for the heck of it, made a quick mock-up of what we have been talking about, added with the exhaust deflector as a bracket for the hoses. The way I see it, the centrifugal force would not throw the fuel out if the hoses were attached as in the second picture. The first pic just shows the components, and obviously there is extra length in the hoses. Didn't want to cut them as I use them elsewhere.

Thanks Kari for the suggestion. I cut and soldered the engine mounting platform to the brass shaft. I tried to get it as straight as pos. It's not easy to snip, drill, file a .5 mm brass sheet while it has to remain flat! I mounted it all dry into the nose block. On the bottom the wheel retainer holds the pivot in position and determines the axial play. Between the wheel retainer and the block is an axial thrust bearing and a steel washer. On top, the aluminium bearing tube protrudes from the block to give clearance for the engine mounting bolts or nuts. On the wood, a round piece of plastic is glued to give the final round outline of the wood. Did I say that the right way?

getback wrote:Wonder if one of these would work ?  and I have a BB 5cc tank that has been drilled , I have never ran either . If you use the small silicone tubing it should stay put ( the stuff for TD engine has a really good grip! Eric  

Eric, that backplate with the single filling thing has a small vent hole next to it, right?

Yes if you blow it up (click on pic) The vent hole is between the filler and the otter screw / The mount is looking good Lieven . That engine is for sale on the bay http://www.ebay.com/itm/281982893548?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649 I may have another back plate I would have to look/ getback

The nose block is glued to the fuse and sanded to shape. On the bottom, I cut a round hole to have access to the shaft. After installing the bearing and wheel retainer, the hole will be covered with Oracover.







A cockpit idea:

I like the idea of drilling the shoulder of a baby bee tank, and using a BW back.  Simple really is good at times.   However staying with the stunt bee tank would be even more simple.

Bernie at Coxengines.com will make a stunt baby bee tank on request.  

Phil

Cutest canopy ever!

I like that gives it that 1950s look of a space ship ! Coming together nicly Lieven got some smooth sanding lines there . Did you decide what your going to do about the engine/tank yet? Eric