FB Gyrocopter Experiments

[Hai-Lee]

I am starting this thread to develop a MAX FB gyrocopter/Autogiro with the aim that a true FB Autogiro that others can build and trim, (prior to first flight) without any maths degree or special equipment and materials.

Whilst my main experimental efforts will be in a single rotor uncontrolled head design the controlled head and the multi-rotor versions will be built and flown as well.

So far as posted on another thread I have used a Tiny Trainer fuselage and have had a few somewhat short flights to date, though one flight actually lasted a full circuit of my local field. With 3 different FB blade designs I have learned a great deal about the head design and future project direction.

I will need more engine thrust as when flying on the rotor the thrust is not quite enough to easily maintain forward flight though I have managed quite a few controlled tail first landings.

HEAD DESIGN:
To date I have been experimenting with materials, (Mostly 1.5mm 3Ply), to give the appropriate flex to allow blade incidence change as the blades flap up and down. I hope to quantify the amount of flex with a weight or torque measurement so alternate materials can be substituted for my materials. Once quantified the head design can be adapted for as many blades as I can fit, (if required).

As the head is fixed, (no control inputs), I have used a plywood platform mounted atop an Aluminium framework. The platform is fixed adjustable for pre-flight rotor incidence adjustments. The rotor shaft bearing is an Outrunner motor mounted directly to the plywood platform and a prop adapter attached to the motor shaft. The head has a plywood flapping angle plate and an Al Lead/Lag limiter bar combined with the plywood bar to which the blades are attached.

BLADES:
So far I have used 3 different sets of 2 blades and tested methods of strengthening the FB without adding CF or similar.
Each blade has an underslung plywood strip and a paddle pop stick in the upper surface of the blade with 3 screws connecting the blade. Makes blade/FB changes much easier.

Next Step:
Build a smaller fuselage or buy a larger motor. (most likely a smaller fuselage because of larger motor requiring larger ESC and Battery).

Today. Tried out the latest set of blades and managed a few "Hops" but lack of thrust caused the usual slow down and loss of control landing. Decided to build a purpose designed FB fuselage to continue project.

 

[Userofmuchtape&glue]

Good job mate, awaiting progress with interest.

 

[Hai-Lee]

Test flights again today to confirm my findings and the results were similar. Two actual flights and no real tendency to roll though I later discovered that I had Power pod damage and LEFT thrust which accounts for the slow turn, (no roll), to the left. Must get new fuselage design finalised and built.

Started constructing the :Teeter: head for the next series of tests hopefully on the new fuselage. A good side by side comparison of ease and simplicity of construction Vs performance.

Hope to post pics from last weeks flight with the large cord blades. Again no camera available today.

Part 2:
Fuselage design complete and construction almost completed. Tail inverted! Greater down thrust built in!

Still using stub Wing but the next time it flys the ailerons and rudders will be connected with a "Y" harness and the elevator will be as normal. With a much larger SF propeller and a lower kV motor I should be able to drag it through the air under control.

Still waiting on the flying pics but a pic of the completed second version should be available later tomorrow.

 

[Hai-Lee]

Attached is a Pic taken over a week ago when I was using the broad blades made from folded FB and a more rigid rotor bar/disk as mentioned in my posts previously. Of note is the very low "Coning Angle", because the rotor bar was too rigid and the blades had too much mass.



They say seeing is believing.

As result of new fuselage a CG point review is in order!

 

[Hai-Lee]

If you are still following Abe here is the new fuselage Just needs a bit of detailing and it will be ready for the next experiments.

Here is a pic of the progress so far. :black_eyed:



Next flying day is Wednesday, weather permitting of course. Sorry the thread is tasking so long but I am recording dimensions and construction details as I go just in cast it actually does fly.

 

[Userofmuchtape&glue]

Your new fuse looks great!

 

[Hai-Lee]

Thanks Abe but I used the Das Parkflyer Stick fuselage as a starting point and adjusted it from there.

Had an epiphany just 30 minutes ago whilst making a few spare sets of rotor blades for tomorrow's tests. I have been using and carving 5mm foamboard and trying to harden it with glue and adding paddle pop sticks and skewers to further improve rigidity without removing the blades ability to flex.

The blade building was getting at the upper end of complexity experienced on this site and could deter others from trying such a build. Tomorrow ,if my current thinking is correct I will have a simple and easy to replicate method for building rotor blades almost identical to each other just using the standard FliteTest methods of score, fold and glue. The reason for tomorrow is that I thought of it just after my FB supplier had closed for the day.

Once the Blades and rotor head are sorted then it will be time for the rotor mast and any changes the test program requires of the fuselage. Will start drawing up the plans on the PC in the next few days for those who may want to try an Autogyro which has no commercial origin or expensive spare part requirements:black_eyed:

 

[Userofmuchtape&glue]

Yes simplicity would mean others would be more inclined to build I think. I have not yet bought my box of flitetest FB, and I have used depron in the past. so, no folds in my technique! I am eagerly awaiting progress.

 

[Hai-Lee]

I had a silly day today. First I ready the craft by fitting my new rotor blades, (new design with skewer reinforcement), rather than the blades from all FB. It was officially windy with others deferring their flying for fear of damage but NOT me.

I tried a high speed taxi run without the stub wing and was hit by a side wind and it fell over. Picked it up, quick check, no obvious damage. Returned to the pits and let others take off/land and readied for another go. Again I did not fit the stub wing and then taxied out this time for a take off run.

It taxied straight and true, built up speed rapidly, and I gave it up elevator to lift off. That is when it all went spectacular.:black_eyed:

The advancing blade lept into the air about 6ft and the craft rolled onto its left side and skidded to a halt. the flying blade took another 4 or 5 seconds to hit the ground. Examined the craft and found no damage to anything except for the rotor bar which had broken of at the inside of the missing blade.

I had spares for everything EXCEPT the rotor bar

I suspect that the rotor bar had been weakened in a previous incident and when I fitted the more rigid blades the rigidity caused more flapping rise at the rotor head and the damaged bar just gave up and failed.

Still was a good day and repairs will take less than 5 minutes. May still need to investigate alternate materials for the rotor bar in the future but for now I have a weakness that I do know of and will carry spares in future.

I will be back flying it next weekend for sure

 

[Userofmuchtape&glue]

That's a pain! do you think the wing would help? Its all a learning experience!

 

[Hai-Lee]

The stub wing allows for a little less accurate build or a more forgiving design. I built my first pair of blades using the new material and following the FT FB techniques. They are far more rigid and stronger but the weight for each blade has risen to 35 Grams compared to the 5mm FB blades which were around 17 Grams.

Slightly harder to work with but results are more uniform and they actually look the part. Once I have a number of blades made while working out the build details I may make a set for a 3 or 4 bladed rotor head using a slight alteration to the rotor blade spare material just for extreme accuracy of the blade profiles.

Should I publish any plans so you can see where I am going with this and what it builds like?

 

[Hai-Lee]

After repairing the damage from yesterdays actions I decided to finalise the "Teeter" head design. It uses the same blades as I have already made. See attached pic.



Time to start the building of the three blade articulated rotor design with the latest version of the blade design!

 

[Userofmuchtape&glue]

Nice! I would love plans for this, A very unique build.

 

[Hai-Lee]

Abe, I will draw up the plans and post them in the next few days. The fuselage was made out of scraps of FB left over from other builds and so there are no A or B folds. The stub wing I will draw as a standard plan FT style.

The aluminium rotor supports and head are just a temporary design but I will include them in a different plan set and the different rotor head designs will be a third plan with the rotor blades yet another plan as I keep adding different blade designs

The final set of plans will be for the final rotor support pylon with a fully articulated rotor head design and servo controls which will replace the stub wing totally along with the aluminium rotor support structure.

Going test flying again tomorrow weather permitting of course!

 

[Hai-Lee]

Another day of mixed results. Initially I could not get it to taxi straight, adjusted motor side thrust and all seemed ok. Fitted rotor blades and attempted a takeoff. it sort of ground looped and broke the rotor cross bar.

Replaced the broken part and went to try again but this time I noticed that there was something wrong. Closer inspection showed that my elevator was reversed. Note to self do not set directions and throws on an inverted tail whilst it is inverted.

With the elevator working correctly I fitted the rotor head and again attempted a take off. It flew, I climbed and banked to the left, leveled off, flew level, banked left again, levleled off again and suddenly the craft started to wobble and vibrate whilst almost directly overhead. It was still controllable so I started a slow descent with yet another left bank heading for the centre of the field when I noticed that one of the blades was bent in the middle and angled up at about 60 degrees.

Landing was rough as there was very little lift and control disappeared as I tried to slow down. Upon inspection the blade was really bent but everything else seemed fine. So I replaced the blades with the heavy new set and attempted a take off almost immediately.

The heavier blades do not spin at the same rate and therefore do not generate as much lift. Upon take off the rotor slowed a little and it fell out of the sky landing on its tail. Test flying over for the day. Tail was hanging by its paper and one of the new blades was bent.

Learned a great deal today firstly it flys. The new material is too heavy for such small blades, and all the controls are now correct and proven in flight.

Off now to reattach the tail and make a few more blades.:black_eyed:

fitted stub wing only and tried to take off, it managed a hop but the speed required was incredible. Good test

 

[Userofmuchtape&glue]

Yay! A start! was that a FB blade that bent? BBQ stick to stop it maybe?

 

[Hai-Lee]

Sadly it was a FB blade and it bent at the end of the paddle pop stick I was using to screw into to mount the blade.

First blades had a cord of 50mm and they were relatively stiff though of poor profile. The one that folded in flight today had a cord of 40mm with a better profile but not too strong. My current set of blades are 45mm cord and have a great Clark Y profile and they are so easy to make it is almost criminal, (once you know how that is).

Right now I am developing, making a 3 blade holder for the rotor blades which is the first real step towards a articulated rotor head with servo control.

 

[Hai-Lee]

Weather!!! No flying this morning due to storm so I spent some time on the plans. The plans are just the fuselage, Tail, and the current blade design.

View attachment FB Parts - Prototype.pdf

The stub wing plan will be the next followed by the current rotor pylon design.

Hopefully tomorrow will be a better flying day.

Sunday: Weather AGAIN! Another day lost but it gave me time to finish the stub wing plan and catch up on a few other designs as well.

Here is the Stub Wing Plan, (borrowed from a biplane design I made):

View attachment Stub Wing.pdf

Pylon and rotor head design/plan almost complete perhaps I will post it tomorrow or later tonight if the mood takes me.

 

[Hai-Lee]

Was called out late this morning and so I managed to do another attempt at flying. This time I fitted the "Teeter" rotor assembly for its first tryout. It was slow to get spinning but it did lift off quite well and climbed to about 5ft where it slowly rolled to the right and crashed.

Obviously it rolled to the retreating blade side and I suspect that the teeter bar was not free enough to balance the lift. Once again I broke the tail off so I was not able to test the new blades on the first rotor head design I have had more success with. Maybe next time?:black_eyed:

 

[Userofmuchtape&glue]

You are very persevering! Thanks for the plans too. I will try to build one when I get some foam. I used the wing of my little 750mm art-tech mustang, and turned the ailerons into elevons, added a motor and whalla! it flys but I don't know how....