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Old Dec 11, 2008, 10:01 PM
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Thanks for the info Jochen. Your design is really great. I will get started on mine as soon as I can, my schedule flying the Full scale helicopters has been getting in the way of my R/C flying. I appreciate your efforts and posts. I'll post when I get started.
Regards,
-Mike
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Old Dec 12, 2008, 01:33 AM
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Ordering materials! Can't wait to start building!

Ok Gentlemen Iím convinced to build the V2. Thanks for the encouragement and posts. You guys rock. Iím trying to sort through all the posts and compile a list of parts. Since there are several versions, I may have confused some things. Iíd appreciate it if you guys could proof this list for me. Peter helped me overcome my build fears, so Iíll stop trying to by ready made parts. LOL (Iíll order from all over the World too Peter ). I may have missed a post somewhere with a completed parts list, if so point me in the right direction please.

Technical data:
DC rotor, three-bladed, 2" Aerobalsa rotor blades
rotor diameter: 930 mm / 36.6"
AUW: 500 g / 17.5 oz.
RC functions: roll (aileron), nick (elevator) and throttle
battery: 3S/910 mAh LiPo
motor: Plettenberg Freestyle 24, 75 g, turning a 9x4.7 APC Slow prop at 8650 /min while drawing 12.5 A
servos: 20 g / 0.7 oz., metal gears

Pivot head
http://www.cenracing.com/cars/ff/fftuningparts.html
and look for item no. FFS004, the universial swing shaft for Buggy/Rally. As the name of this item is a bit long, I'll refer to it as the CV joint from now on.


The first major changes concern the airframe (see Airframe drawing). Both the rotor mast as well as the support strut now have an O.D. of 5 mm, there's no bottom plate any more - that's why the main boom has grown out front -, and there's a new motor mount. The list of materials needed for the airframe now looks something like this:
- one piece of cf tube, O.D. 8 mm, I.D. 6 mm, length 170 mm
- one pieces of cf tube, O.D. 6 mm, I.D. 4 mm, lenght 120 mm
- one piece of cf tube, O.D. 5 mm, I.D. 3 mm, length 290 mm
- one piece of cf tube, O.D. 5 mm, I.D. 3 mm, length 230 mm
- one piece of cf tube, 6 x 6 mm, I.D. 4 mm, length 80 mm
- one piece of aluminium or brass tube, O.D.6 mm, I.D. 5 mm, length 35 mm
- one wheel collar, I.D. 6 mm
- two wheel collars, I.D. 8 mm

-http://www.flugmodellbau.de/index.p...bre-sheets.html
Glass fibre sheet 300x135x0,5mm
(Thats 11.8" x 5.3" x 0.02" )

-Motor (which I already have)
APC 9x6" slow fly prop, the AXI 2212/26

-6 mm Depron Tail and pilot
-3mm nylon screws

-three 2" Aerobalsa rotor blades of 450 mm length
-Ply for the head
-Wheels???
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Old Dec 12, 2008, 03:30 AM
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Go for it Mike

If you are intending to ROG, I suggest you add a Rudder.

Other odds and sods that you will need...
Velcro (hook and loop) for the pilot and battery.
Ball joints and control rods for the head (and rudder).
Carbon Fibre ribbon for binding the airframe joints.

Ask Jochen to send you the "all in one document" version of the build instructions (if he hasn't already done so). He also has some modified instructions for the nose wheel.

I'm sure you'll keep us up to date with your progress

PeterO_UK
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Old Dec 12, 2008, 06:30 AM
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Mike,

add this to your shopping list:

For the front wheel suspension you'll need:
- one piece of cf rod, O.D. 4 mm, length 150 mm
- one piece of cf tube, 6 x 6 mm, I.D. 4 mm, length 40 mm
- two pieces of beech wood, 6 mm x 5 mm, length 40 mm
- one piece of cf sheet, 1.5 mm thick, 25 mm x 85 mm
- four pieces of cf rod, O.D. 2 mm, length 8 mm
- one piece of cf rod, O.D. 2 mm, length 30 mm
- one wheel collar, I.D. 6 mm
- two wheel collars, I.D. 2 mm

Some more ply and balsa for the motor mount.

The wheels are the usual slow fly wheels with a diameter of 64 mm / 2.5".

Jochen
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Old Dec 12, 2008, 06:56 AM
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Minimum update

Because of last years flying experiences - or better: landing experiences - I've changed the design of the front wheel unit. The new unit is not bolted to the front rod any more, it is held by a simple wheel collar/grub screw. This makes it very much easier to change the 4 mm front cf rod, which - as you know - is a predetermined breaking point. The genaral dimensions have not changed, and it's possible to modify existing front wheel units without too much work.


The Front Wheel Assembly (‘MotorMount&FrontWheel’ drawing)

For the front wheel suspension you'll need:
- one piece of cf rod, O.D. 4 mm, length 150 mm
- one piece of cf tube, 6 x 6 mm, I.D. 4 mm, length 40 mm
- two pieces of beech wood, 6 mm x 5 mm, length 40 mm
- one piece of cf sheet, 1.5 mm thick, 25 mm x 85 mm
- four pieces of cf rod, O.D. 2 mm, length 8 mm
- one piece of cf rod, O.D. 2 mm, length 30 mm
- one wheel collar, I.D. 6 mm
- two wheel collars, I.D. 2 mm

Here's that odd bit of square cf rod again. Sand the front 5 mm of the square tube round, so that the rounded part has an O.D. of 6 mm. To replace this part, epoxy a 40 mm long cf tube with an O.D. of 6 mm and an I.D. of 4 mm into a 35 mm long cf tube with an I.D. of 6 mm, the rear ends flush. Then sand the top and sides - if there are such things - of the outer tube down to the inner tube, and you've got something which, while not being exactly square, will do.

Cut the 1.5 mm cf sheet into two parts of roughly the size of the wheel supports and fix them together with some double-sided adhesive tape. For this kind of operation I'm using the type of tape which is normally used for sticking photographs into albums, it's thin, just strong enough and easily removable. Now print out the shape of one support on a sticky label of the right size and stick it onto the cf. Then cut the supports down to the correct size and drill the 2 mm holes for the axle and the two 2 mm bolts. Take those two supports apart again. Use the same method to stick the two beech wood pieces together and stick one of the wheel supports onto the side of this pack, correctly aligned, of course. Use the holes in the support as a template for drilling the two bolt holes into the wood. Remove one piece of beech wood, replace it with the 'square' cf tube and drill again. Take everything apart again.

Epoxy the 6 mm wheel collar over the front end of the central cf part, the hole for the grub screw facing downwards. Don't worry about epoxy getting into the grub screw hole. Remove some of the wood at the front ends of the beech spacers to make them fit around the wheel collar. Epoxy the spacers to the cf central part, using the bolt holes as a guide (slip the 2 mm rods through the holes and remove them after you've got everything correctly aligned). Now glue the cf wheel suspensions to the sides of the spacers with some contact glue - I used UHU por -, using the holes and bolts as guides again. Fix the four 2 mm cf rods in the bolt holes with silicon. The short pieces of cf rod help feed any force on the wheel suspensions into the rest of the unit. Tape the rear end of the whole unit and the part behind the wheel collar with resign drenched carbon tow. The cf wraps now hold everything together and prevent the wood from splitting up. Iin case you've crashed head-on and broke one of the wheel suspensions, you can use a sharp knife to remove the cf wraps and - because of the contact glue used - to peel off the damaged suspension from the wooden spacers. Drill a 2.5 mm hole through the grub screw hole of the wheel collar and the underlying carbon, put the 4 mm rod into the front unit and use the grub screw to remove any remains of the epoxy and to fix the rod.

Now you've got a front rod that can be changed by just loosening two grub screws. If this rod breaks off near the airframe, it's helpful if you have a 1.5 mm hole drilled from the bottom rear through the wrap securing the mast support into the tube holding the rod. Through this you can push a bit of wire to remove the 4 mm rod, though most of the time it's sufficient if you put the front end of the airframe into your mouth and suck the rod out. Finally round off the edge of the hole that takes the front rod. A sharp edge at that point makes the rod break more easily.

The suspension just described will take the usual 65 mm slow-fly wheels, which have a width of just below 14 mm. If you are using thicker wheels, you'll have to increase the thickness of the beech wood parts to the size of your tires.

The axle for the front wheel is a short cf rod with 2 mm diameter, held in place by wheel collars at both ends. I've enlarged the original hole in the front wheel to a diameter of 3.2 mm. Into this hole I've pressed a 15 mm long piece of my ever-present outer bowden cable tube. This has an O.D. of 3.2 mm and an I.D. of just over 2 mm and gives you the perfect fit for the 2 mm axle.

Jochen
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Old Dec 12, 2008, 04:15 PM
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Jochen,
I sent PM reference the all-in-one document Peter referenced. Thanks in advance,
-Mike
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Old Dec 12, 2008, 04:31 PM
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Mike,

done.

Jochen
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Old Dec 12, 2008, 04:33 PM
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Thanks very much Jochen. I am already ordering parts. Once I have all the components, I'll keep you guys updated on the build.
Regards,
-Mike
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Old Dec 19, 2008, 02:13 AM
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Getting closer

Hello Jochen,
I have ordered most of the materials to start my minimum build. I have a CV joint from an HPI Nitro truck, and I believe it has similar dimensions to the one you used. Do you have those dimensions by chance. If not there's another part to order. LOL I am still a little confused about the bearings used on the CV shaft, what holds the bearings inside the head plate and prevents the head from departing the aircraft? Do you have any additional photos of the head/CV set up? I need a "CV head set-up for Dummies" book. I'm also confused about attaching the CV to the mast. Thanks in advance.
Regards,
-Mike
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Old Dec 19, 2008, 04:14 AM
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Mike,

Look at my build log at
http://www.peteronion.org.uk/Autogyros/Minimum/
You'll find pictures of the bearings glued into the trianglular head plates, and pictures of the collar I used to hold the CV joint into the top of the mast. A friend made me up a rather "posh" part, but a simple collar is what Jochen uses.

If you look closely you can just see that I have put a washer between the top plate and the thrust bearing. The washer is larger diameter than the bearing in the plate so that the load is spread onto the wooden part and not all taken through the bearing. I'll take a close-up picture this evening if you want a better look at it.

PeterO_UK
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Old Dec 19, 2008, 05:39 AM
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Mike,

I've got a 3D pdf-file of the CAD version of my Minimum v2. Unfortunately it is too big to upload on the forum (6.4 MB). Using the Acrobat 3D functions, you can take the pdf model apart, down to the last grub screw, and have a close look at how things are done. If you're intersted, PM me your email address and I'll pass it on to you.

Jochen
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Old Dec 19, 2008, 03:50 PM
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Jochen,

How many Minimums do you think have been built ?

PeterO
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Old Dec 19, 2008, 05:40 PM
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Peter,

I know of four. Two in Germany, including mine, one in Switzerland, and yours.

Jochen
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Old Dec 19, 2008, 11:57 PM
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Peter,
I've been watching your build page closely. It's incredibly helpful, thanks for the time and effort you've put into it. I have ordered everything for the build, less a few items I already had on hand. When I get a few packages in I'll get started right away.
Have a great weekend!
-Mike
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Old Dec 20, 2008, 02:45 AM
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Quote:
Originally Posted by JochenK
Peter,
I know of four. Two in Germany, including mine, one in Switzerland, and yours.
Jochen
Oh, I am surprised that the number is that low !

Who will be No. 5 ? Bones or GeeW ?

Come on Gordon, hows it going ? Mike will be catching you up soon !

PeterO_UK
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