Fire Fly 2 autogyro build

[Foamie Dave]

You not finished it yet D ?

Nice job , looks to be coming along a treat

[simon burch]

Hang it by the rotor head and check the angle of the boom, should be hanging down by 14-16 degrees (that's what mine flies at but Rich will clarify)

Set the head plate at right angles to the mast. Make sure you have about 15 degree tilt left and right (add some dual rates here). you can have as much back tilt as you want, but you should not be able to push the head plate past 90 degrees to the mast when pushing full forwards stick (negative forward pitch angle on the head is bad news, unless you like rebuilding !!) Again use a dual rate to set this up.

Choose a nice day with a little breeze, hold her above your head till you hear that lovely whistle on the blades (angle her back to let the wind spin the blades) and then 2/3 throttle and a little push and you are officially an autogyro pilot.

Remember height is controlled by throttle, so once she has gained a bit of height, come off the power a bit. Keep it close, its vey easy to get disorientated.

Here is my maiden, but you might want a bit more of a breeze for a maiden

Don't let her go if the blades are not whistling, or she will just roll left and smash into the floor. ROG's are fun, but I would save that until you get used to hearing when the blades are ready to fly.

Cheers,

Simon

[Grasshopper]

Thanks Simon, all very clear. Just one small thing though on the fore/back setting.

You say to have as much back tilt as you want/can but not to have ANY forward tilt. In the idle state at the Tx with the elevator stick self-centered is the fore/aft tilt of the head plate zero? If so I asume that moving the stick foward has no effect on the head plate and of course moving it back gives the rearward tilt you mentioned. Is this correct?

Oh, and nice video, you made it look so easy!

David,

I just grabbed some 3mm Depron and a sheet of 3mm balsa and my digital scales. Per metre square Depron is 121g and balsa 357g (yes ok, depends on the piece of wood, soft, light etc.) The relative glue weight should be much the same.

Thus - on the tail where weight is always a killer, I would go for Depron if you can.

Peter

[simon burch]

No, no.....when the sticks are at neutral, the head plate is at 90 degrees to the mast looking from the side and the front (so relative to the boom, the head will look like its tilted back as the mast is also raked back). When you give full forward stick, you only want the head plate to pitch forward to the point its parallel with the boom. If it goes further forwards, the machine may tuck under and you know the rest from there !!!. You may find after your first flight that you add more rear trim to slow her down. I can't give you an exact amount because they all fly slightly differently,even the same model deisgn will have its own little character.....that's what makes them so special to fly.

I just tweaked the dual rate numbers so that forward stick movement stays the same, but I have the option of more rear movement if i want to mess around.

As long as you have everything set up, it is that easy. The Firefly flies like a trainer that you can't stall, but the main thing which will spoil your fun, is trying to launch or take of without the blades being up to speed.

Looking forward to hearing about the maidens. Can post a little vid of the head moving on my Firefly if it will help? Rich might already have something?

Cheers,

Simon

Edited By simon burch on 24/10/2012 15:00:06

[Grasshopper]

Hi Simon,

yes I get it now - in my words for you to confirm:

Sticks idle, plate at right angles to mast in back/fore and left/right directions.

Stick full forward plate tips down at the front until parallel with boom and no further.

Stick full back, plate tilts back as far as you can get.

Right and left stick movements tilt plate towards right/left.

Do I get it now?

Peter

[David Ashby - Moderator]

Thanks Simon. A video would be great if you can

So......given that....and sorry if this sounds a bit obvious.....

Rudder = yaw (in the normal way)

throttle = speed and height

ailerons = bank (in the normal way) and...

elevator = pitch control

It almost sounds as if you're fying the blades rather than the fuselage? Assume you use rudder to bring the fuselage round in turns much like a heli?

[Richard Harris]

David,

The blades are a very efficient brake, the more they are tipped rearwards the more drag is enduced so more energy is needed to maintain forward flight. At speed the rearward tilt will make it pitch its nose in the normal way but at slower speeds high alpha flight is more than possible with a bit of throttle management using this drag and lift to our advantage.

Try not to think of it as a heli but as a fixed wing, kind of having a round wing on the top.

 

This is an old video of my 3rd model,you can easily see the amount of drag there is involved and how it can be controlled with throttle.

 

 

 

The boom and template are the datum point for any angles, these angles will differ from model to model due to weight, blade lift etc

But, rule of thumb is a hang of between 12-18 degrees with a rotor rearward tilt of around 5 degrees foor level flight.

 

3mm depron is a bit thin, I see no reason why balsa can't be used. Just look at Tom's Crane flies, they fly exceptionally well and do use 3mm balsa for the tail end.

 

Rich

 

Edited By Richard Harris on 24/10/2012 16:34:43

Edited By Richard Harris on 24/10/2012 16:38:28

[Martin 10]

Hi there,

Setup is usually difficult to explain to beginners, but is real easy.

1) Get your tailboom level.

2) Transmitter sticks at midpoint (make sure motor is unplugged)

3) Looking from side of FF: Set adjustible spirit level on 6 deg and now put it on the head and adjust to suit spirit level.

4) Now set your spirit level to zero, push elevater stick forward, set travel on on servo until bubble is centre.

5) Now 15deg. Pull elevater back (I use an elastic band on the stick to have both hand free) and adjust TX to centre bubble again.

6) Now stand behind the gyro, set spiritlevel to 2deg. The rotorhead should now have a 2deg to the left tilt with ailron stick in the middle.

7) Now do a 15deg left and right tilt using the same methoud as above.

8) Set TX to exponential and set that to 15 or more.

[David Ashby - Moderator]

Thanks Rich, good stuff. More progress this evening.

Front end sanded and hatch made.

Tail feathers made from sandwiched 3mm Depron.

...and the tail mount assembly started using the carbon boom as a guide.

[simon burch]

On the Firefly, the best base setting is just to have the plate at 90 degrees to the head in all directions. It may need a bit of trim, but it will pretty much fly out your hand.

[David Ashby - Moderator]

A little more, I made up the tail feather support last night.

 

Edited By David Ashby - RCME on 26/10/2012 09:44:18

[Grasshopper]

Nice work David. I'm afraid being a Depron nut I did the whole thing sans-balsa.

Been thinking about measurnig these head angles and not poessing a suitable tool, I decided to make one.

It took 30 minutes and cost me €4.50 - or about £3.60 to you.

Simple, buy a cheap protractor, cut a piece of scrap fibreglass board, 0.8mm is fine. Cut the board as shown, scribe a line at exactly right angles to the 'top' side and then drill a 2mm hole in the board and in the protractor centre point.

At a hardware shop I bought a 'Dexter' spirit level for checking the level of chords set horizontally and used when wall building. Here in France these cost less than £3 but if you cannot find one then in a £1 shop buy a spirit level and rob the bulb. Glue the 'Dexter' part or alternative to the top flat side as shown and use an M2 bolt and nut to attach the two parts. Tweak up until there is just enough friction to hold the desired setting.

Peter

[David Ashby - Moderator]

That's a bit of handy thinking there Peter and I think I may have all the bits I need to make up one of those. Off to the shed for a rummage ......

Have you made your blades yet? How did it go? I was wondering whether thin ply would suffice instead of the fibreblass sheet at the root area? What do you think?

Edited By David Ashby - RCME on 26/10/2012 10:23:49

[simon burch]

David,

I just used thin 1/16 ply at the roots of my blades. Rich used g/f because he had some off cuts. The reinforcement is there to stop the bolt pulling through the blade root.

If you look in the picture, you can see the little ply reinforcements already expoxied in place on the top, and the ply plates waiting to be glued underneath.

Here is another picture from underneath of another set of blade (same design of blade)

If you are going to maiden over one weekend, let me know and I will pop over for a look.

Cheers,

Simon

Edited By simon burch on 26/10/2012 10:39:53

Edited By simon burch on 26/10/2012 10:42:28

[David Ashby - Moderator]

That's great thanks Simon - saves me buying the fibreglass sheet when I've loads of ply to hand.

That's very kind, yep I'll certainly let you know re a meet up

[Grasshopper]

Blades look good Simon, this is the bit I have left to last!

In fact when I ordered the head from HK I also bought a set of C30 blades as they cost less than a fiver. Rich made a comment in a post that he had tested them in a FF2 and they worked fine but that it flew a little bit fast.

I have started making my own blades and depending on weather and when the rest of the FF is complete - I may maiden with the HK set.

Peter

[David Ashby - Moderator]

Have you got the link to the HK set Peter?

[Grasshopper]

David, this is the link.

C30 blades

Amazing value for money, they even come ready covered!

Just off to buy some better 6mm balsa for my home-made set as the stuff I have here looks a bit scrappy.

Peter

Edited By Grasshopper on 26/10/2012 13:16:36

Edited By Grasshopper on 26/10/2012 13:16:52

[David Ashby - Moderator]

Thanks Peter, I think I'd better get some just in case. That Cievra C30 looks nice!

[Richard Harris]

David,

I have tried the HK blades on mine and it did fly but it felt heavy and fast, it also was a bit of a pig to get them up to flying speed.

There hasn't been many of the HK C30's get into the air, they are a bit heavy for their size. With a few mods and different blades they seem not to bad.

The C30 is an autgyro that is high on my list to model

Rich

[Grasshopper]

Thanks Rich for the detailed update on the HK C30 blades: it looks like I'd better get blade bashing and put those to one side for now.

I just managed to replace the scrappy 6mm balsa I had with a couple of nice sheets within 2g of one another so just about to get out the knife and get cutting and sandwiching.

Peter

[David Ashby - Moderator]

Yep, thanks Rich - I've ordered some blades but I'll put them away until I'm an autogyro hooligan

Started on the tail feathers, Gorilla Glue seems to be working well for the Depron and Depron/balsa joins.

Oh, and I've bled on it for the first time so it's now christened - It doesn't normally take this long

[David Ashby - Moderator]

The story so far - all the woodwork and Depron work done so now it's time to decorate - I'm going for a silver scheme as I've some spare film and I'll spray the tail feathers.

[BILL PETTIT]

Looks nice Dave !

Bill

[Steve Hargreaves - Moderator]

Looks Good David.....serendipity about the cowl fitting....

How does the plan suggest you make the blades? Sanding to section from balsa? Reminds me of the wooden heli blades I used in the early 90's...these had a hard (ish) wood LE & a balsa TE & some lead set into the LE near the tip to bring the blade CoG forward covered with white heatshrink tube......