Crane Fly Trainer Autogyro

[Steve W-O]

Post duplicated

Edited By Steve W-O on 19/01/2012 01:01:20

[Tom Wright 2]

Hi Steve .

Yes I absolutely agree with your comments ,but all the padding that makes continuity difficult and turns the thread into a long read can contain lots of usefull info and links to help the fist time gyro flyer get into the subject .

 

Long diatribes on theory and precision engineering are likely to put many off that's why I have endeavored to present the thread in a practical and simple way .

 

My own experiences and watching the failed attempts of others to build and fly gyros ,was turned around in one day when my first predecessor of the Crane Fly was taken to the field and flown successfully by four pilots who had previously failed or never flown a gyro.So the thread is based on what worked for me and the guys at the field.

 

A little know how on set up trimming and pilot technique should be enough to get some that may have never tried airborne with a simple lightweight auto gyro .

 

It would be fair to say that autogyros have been in existence for seventy years so why are they not sen in every hanger like WOTS Spits and Super Sixties ? what ever happened to aeromodelers curiosity ? has it been destroyed by plug and play ARTF and the like? who knows !... so there you go more padding for the thread the only thing I know for sure is my own "Crane Fly" will fly and its built exactly to the specs posted on this thread.

 

If it gets a handful of new pilots interested in this branch of aeromodelling then I will have done a little to assist Rich in his quest to attract more enthusiasts and returned the effort he put in to get me interested.

 

Tom.

[Tom Wright 2]

Posted by Tom Wright 2 on 19/01/2012 00:34:55:

After a lot of searching I found a UK supplier of 1mm smooth both sides woven laid GF.

Not cheap at £9 odd but one sheet should make three tri plates or two and enough left over for the other components .

 

Or if you build a larger scalloped tri plate this 1.6mm GF is excelent.

 

Take a look and if you know of a cheaper source please let us know.

 

To build a more sophisticated control mech this universal joint might come in handy for future gyro projects.

 

Tom.

 

[Steve W-O]

Posted by Tom Wright 2 on 19/01/2012 01:55:04:

Hi Steve .

Yes I absolutely agree with your comments ,but all the padding that makes continuity difficult and turns the thread into a long read can contain lots of usefull info and links to help the fist time gyro flyer get into the subject .

 

Long diatribes on theory and precision engineering are likely to put many off that's why I have endeavored to present the thread in a practical and simple way .

 

My own experiences and watching the failed attempts of others to build and fly gyros ,was turned around in one day when my first predecessor of the Crane Fly was taken to the field and flown successfully by four pilots who had previously failed or never flown a gyro.So the thread is based on what worked for me and the guys at the field.

 

A little know how on set up trimming and pilot technique should be enough to get some that may have never tried airborne with a simple lightweight auto gyro .

 

It would be fair to say that autogyros have been in existence for seventy years so why are they not sen in every hanger like WOTS Spits and Super Sixties ? what ever happened to aeromodelers curiosity ? has it been destroyed by plug and play ARTF and the like? who knows !... so there you go more padding for the thread the only thing I know for sure is my own "Crane Fly" will fly and its built exactly to the specs posted on this thread.

 

If it gets a handful of new pilots interested in this branch of aeromodelling then I will have done a little to assist Rich in his quest to attract more enthusiasts and returned the effort he put in to get me interested.

 

Tom.

 

 

 

Tom, I agree with your aims, not criticising at all, I was just commenting on the difficulties of following the plot for someone coming in a good while from the start.

 

As for gyros not being more widespread, I think that may be due to lack of information.

Obviously people know the info (well at least one would hope so) but it is very hard to find a to-the-point summary of gyro design, contrast that with how easy it is to find a similar summary of planes or even helicopters.

 

There are threads like yours that show how to build a flying one, but why is the mast at that angle, why is it that long, why has that disc area been chosen, why a flapping hinge, why are the blades free to move and not rigidly fixed to the hub.

 

The last one could be answered in a couple of lines, I shouldn't think it would take more than a couple of pages to give a run down, it does not have to be technical, anybody who wants the maths can do further research.

 

So, I don't think it is modellers lack of curiosity that prevents them trying gyros, I think it is because of their curiosity that can't be satisfied

[Richard Harris]

Steve,

What you are probably viewing is forums looking for information? Of course threads will build up and most aren't interested on why and how things are done, they just want to build a model that gives them half a chance at a flight.

I'm sure that the magazine editors don't get questions every month about a certain plan asking why the designer did it that way etc The build and all the relevant info is normally there in the write up. But that is a magazine and is free from the intrusion/ replies from others.

There was a cracking site for anyone who wanted to design there own and put things into simple terms, I have just checked and it seems the main page is there but the links aren't working at the moment.

 

RC Autogyros

 

To answer the few questions above.

 

Why is the mast at that angle?

 

The mast angle only helps move the CG position forwards. Another way would be to lengthen the nose. If you look on some modern pusher type autogyros the mast is angled forwards, done for the same reason except pilots weights have to be taken into consideration, hence the rake forwards. The CG position is very important and I can do a simple drawing why it has to be so far forwards?

The important bit is that the rotor disc has to be tipped backwards, with an autogyro the air direction is up through the rotors to keep them spinning. A good starting point is 5 degrees but each design will be different.

 

Why is the mast that height?

 

Again its to do with the CG position, the rotor disc has to be well above the CG position. The higher it is the more stable the model but roll control becomes less effective the further you get from the CG position.

The shorter the mast the more responsive the controls get but it gets more likely that the rotors will strike the tail.

 

Disc area...why?

 

As with fixed wings it all depends on the weight of the model to what span is chosen for that particular model.

 

2.5 oz - 5oz per square foot is what should be aimed for.

 

Why a Flapping hinge?

 

If you took your newly finished fixed wing up to the field and tried to fly it with just one wing panel you can guess the results. The same thing would happen to an autogyro if the blades were fixed rigid to the hub, the blade moving forwards into wind is travelling faster than the one going down wind. So it is producing way more lift and will just roll the model over to the opposite side of the forward moving blade.

By making the hub hinged or 'flapping' this enables the blade to lift or flap. There is a lot more to it but it in simple terms it alters the angle of attack of each blade through a rotation. This evens the lift making it stable.

 

Why are blades free to move and not rigidly fixed to the hub?

 

Easy really, they can be fixed to the hub but if they are they have to be accurately drilled and positioned, get them slightly out of position and they will be out of balance. A single mounted blade is a 'scape goat' for us as this enables the blades to find there own position. A bonus in 'an event' is that the blades are less likely to get damaged when they strike something.

 

 

Rich

[Tom Wright 2]

 

Steve.

I think it would be fair to say that there is a big difference between a build thread and a

thread aimed at discussing the theoretical aspects of autogyro design.

Intertwine the two and things become even less readable than the average build blog with its interventions and chit chat.This is why I have not included any autogyro design theory here,although it would be a good idea to have a separate thread lead by designers for the benefit others wishing to learn the theory and design their own models.

 

Popular plans and kits don't usually contain any design theory ,people just build them and take note of CG and trimming requirements ,so its hard to see why a lack of information does not inhibit the potential builder?

 

Several people who live within convenient driving distance from "the field" have already completed models based on my "Crane Fly" and come along to get advice on how to set up and trim the model ,following the advice resulted in successful flights ,but my point is that these pilots new nothing of autogyro design or the associated aerodynamic

theory ,but it did not put them off having a go.neither did it get in the way of learning how to fly the model ,so I just fail to see how lack of information is the principle barrier that prevents modelers having a go.

 

Should some who can fly fixed wing with confidence achieve a degree of early success with simple autogyros decide to continue in the autogyro grove then certainly the basic theory would be a represent another "tool in the box "and as all the other relevant information is assimilated either through study and or practical experiance own designs could then be attempted.

 

My theory is that if most flying club flight lines had a couple of autogyros in the line up then things would be very different indeed, just one in our line up has inspired several of the regular guys to build ,and get flying. .Yet another factor is the popularity of helicopters, may be autogyros are regarded as the poor relation,and look what happened to full size auto gyro development in the early 40s the development of the helicopter left them in the shadows bereft of funding .

I can only repeat that for me the autogyro has been a very welcome and interesting change from 60 years of fixed wings of all forms.

 

Tom.

 

 

 

Edited By Tom Wright 2 on 20/01/2012 02:37:09

[Steve W-O]

Posted by Tom Wright 2 on 20/01/2012 02:36:39:

 

Steve.

I think it would be fair to say that there is a big difference between a build thread and a

thread aimed at discussing the theoretical aspects of autogyro design.

Intertwine the two and things become even less readable than the average build blog with its interventions and chit chat.This is why I have not included any autogyro design theory here,although it would be a good idea to have a separate thread lead by designers for the benefit others wishing to learn the theory and design their own models.

 

I agree totally, my point was that information on even basic concepts is hard to find.

What it needs is a theory thread, and a theory chat thread, so that the theory thread can be a useful reference.

Popular plans and kits don't usually contain any design theory ,people just build them and take note of CG and trimming requirements ,so its hard to see why a lack of information does not inhibit the potential builder?

 

Perhaps if there was a selection of gyro kits at the LMS that could be said to apply to gyros?

 

 

Several people who live within convenient driving distance from "the field" have already completed models based on my "Crane Fly" and come along to get advice on how to set up and trim the model ,following the advice resulted in successful flights ,but my point is that these pilots new nothing of autogyro design or the associated aerodynamic

theory ,but it did not put them off having a go.neither did it get in the way of learning how to fly the model ,so I just fail to see how lack of information is the principle barrier that prevents modelers having a go.

 

I don't know what comment that refers to, in one post I was commenting on the fact that only about 20 had been built, and another comment I made was that if modellers were curious, they would want to know more. There will of course be many that will build anyway, my comments were in reply to other comments.

 

Should some who can fly fixed wing with confidence achieve a degree of early success with simple autogyros decide to continue in the autogyro grove then certainly the basic theory would be a represent another "tool in the box "and as all the other relevant information is assimilated either through study and or practical experiance own designs could then be attempted.

 

My theory is that if most flying club flight lines had a couple of autogyros in the line up then things would be very different indeed, just one in our line up has inspired several of the regular guys to build ,and get flying. .Yet another factor is the popularity of helicopters, may be autogyros are regarded as the poor relation,and look what happened to full size auto gyro development in the early 40s the development of the helicopter left them in the shadows bereft of funding .

I can only repeat that for me the autogyro has been a very welcome and interesting change from 60 years of fixed wings of all forms.

 

Tom.

 

 

 

Edited By Tom Wright 2 on 20/01/2012 02:37:09

 

 

I am in no way trying to be critical of your efforts, as I said before I like the way of thinking and the effort you are putting in.

 

My initial comments were in reply to Richards comment that so few had been built despite his time and effort, and to yours about what happened to modellers curiosity.

I find the long and winding thread difficult to get the information out of, having started to read after it was all over, and being curious, I want to know the basics and how they fly.

 

 

I'm reading this thread in interest, as I have been looking at building one for a few years now, but in the time I have available, have not found the info I need (need is probably the wrong word, as I don't need it to build, only to satisfy my desire to know how it works)

 

I sincerely hope your build does promote more interest, as that will promote more posts and the spread in info.

[Tom Wright 2]

Had a call today from Graham from Bucks - Composites today apparently we have cleaned him out of the high quality1.5 MM GF sheet.

New stock will take 7-14 days .

All the chopped strand 1.5 Pete laid up has also gone ,but I have enough on hand to send to one or two who want to get on with the build, pm me if that's you.

 

Tom.

[simon burch]

Well, a whole page (almost) on the problem of padding out a build thread ???

 

Anyway, back on track..........time for a photo.

 

Been struggling to find the time to cut out the ply parts and get them sanded (my shed is up but not kitted out). Then I remembered the beautifully equipped DT department at the school I work at. Ten minutes after school and job done.

 

Is there going to be another plate on the front before mounting the motor ??

 

Cheers,

 

Simon

[Tom Wright 2]

HI Simon.

Nice work and pdq as well !

Don't forget the former that fits in between the uc were it locates on the fire wall .

Your ahead of the build thread now as fitting the uc and motor will be covered in the final assembly notes.

If you want to get on, you can fit the motor after gluing the uc former in place... then when every thing else is finished locate the uc and secure with saddles.

 

Have you got the flanged bearings? if not give me a shout .

 

Keep up the good work

 

Tom.

[Lazygit]

Posted by Tom Wright 2 on 20/01/2012 18:31:03:

Had a call today from Graham from Bucks - Composites today apparently we have cleaned him out of the high quality1.5 MM GF sheet.

New stock will take 7-14 days .

All the chopped strand 1.5 Pete laid up has also gone ,but I have enough on hand to send to one or two who want to get on with the build, pm me if that's you.

 

Tom.

Hmmm, you did this with Robotbirds and the Rotorshape spares. You can't go on causing world famines of this nature.

[Tom Wright 2]

Crane Fly Autogyro

 

Rotors continued

 

Now the rotor blades are sanded to section with the gf tongues fitted the next job is to CYNO 1.5mm CF to the leading and trailing edges .

 

The CF can be found in RC SPARES AND ACCESSORIES on the giant cod site page 57.

At £6.75 for 10 1m lengths its good value and handy to have around.

 

 

 

 

Edited By Tom Wright 2 on 20/01/2012 20:41:18

[simon burch]

Still got the head and stuff to sort out. Too tired tonight, but its been sitting in the same state for over a week and I just wanted to glue a few bits on.

 

Ordered the bearings and they arrived today, so all sorted on that front.

 

Might try and get that done over the weekend, but I've got a lot of other work to do. Still got the blades to glue together etc.

 

Cheers,

 

Simon

[Tom Wright 2]

Hi LG

Good to hear from you again and thanks for the RC Bearings link its a good one and they seem well stocked so the up turn in autogyo building should not be a problem for them .

 

Tom.

.

 

[Malcolm - coolwind.co.uk]

Tom

Is this a Carbon Rod or Strip?

Can you show a picture of how the Rod/Strip fits against the profiled blade

 

Thanks

Malcolm

 

[Tom Wright 2]

Its CF solid rod Malcolm, just done a quick lash up for a photo hope that enough to see how its positioned.

A 1.5 MM grove could be made along the LE and TE edge profile to accept the rod half section but I have not found it necessary,although it would be good practice.

 

[Malcolm - coolwind.co.uk]

Great, Thanks.

[Tom Wright 2]

Crane Fly Autogyro

 

Rotor Blades continued Preview of next stages.

 

Its up to the individual builder but I would recommend the rotor blades are not covered ,this is to make repairs quick and easy while in the learning phase.

 

When the builder has completed the work to date the next step is to add some negative twist to each blade ,I have done this by steaming on all my previous autogyro blades, and it seems to work well ,the conventional way of achieving this is to fix a 1-2 mm wedges on the tri plate so the blades are angled LE down by 2-4 degrees ,The angle should be as low as possible but sufficient for the rotors to run up vigorously in a light breeze.

 

Rotor blades should be sealed when completed and before balancing ,I simply brush on a coat of lightly thinned PVA ,Dope, or several types of preparations found at the LMS or on line will do but could be more expensive .The total weight of each finished blade should be around 25gm.

 

More on these next steps to come in the next few days as the flying weather outlook is not so good .

 

Tom.

 

 

[Tom Wright 2]

Here is the link to the UK flanged bearing supplier its possible that we have "cleaned them out" as well ,if so pm me I have some that can be posted.The bearing ref is ...

3x8x4 flanged Bearing (x1) F693zz Price £1.25 each.

 

Tom.

[Tom Wright 2]

Posted by Steve W-O on 20/01/2012 05:08:06:

 

I sincerely hope your build does promote more interest, as that will promote more posts and the spread in info.

 

Thanks Steve.

 

Tom.

[Tom Wright 2]

Crane Fly Autogyro

 

Rotor blades continued

 

The rotor tips are reinforced with 1/16 ply end ribs ,this greatly reduces the chance of splits resulting from ground strikes.

 

 

 

Edited By Tom Wright 2 on 21/01/2012 18:28:57

[Tom Wright 2]

Crane Fly Autogro

 

Rotor blade continued

 

The blade twist was achieved by holding the blade half way along between fingers and thumb ( left hand thumb on t/e ) and at the tip in the same way (right hand).

 

The blade was then held over the steam source ( I used a jug kettle) concentrating the steam about 6ins in from the blade tip,taking great care not to get fingers or hands burnt. After a few seconds exposure to the steam apply a twisting force at the tip end as a twist develops remove from the steam and hold the twist in for 30 secs or so .

 

Lay the blade on a flat surface and check that the last 6in of the t/e is progressively turned up to a maximum of 1/4" at the tip.

 

To ensure equal amounts of twist in each blade weight down up to 6" from tip and place 1/4" packing under the t/e tip.

 

Edited By Tom Wright 2 on 21/01/2012 21:11:49

[simon burch]

Done a bit more tonight, got the head and hinge made but used 1/4 square spruce for the control arms as that's all I had. Got the piano wire ready, but need to laminate some ply for the infill piece. Hopefully get the head and pitch fork finished in the week, then onto the blades.

Cheers,
Simon

[Tom Wright 2]

Hi Simon

Thanks for posting progress sounds like you will have it finished in no time at all .

 

Tom.

[Tom Wright 2]

Crane Fly Autogyro

 

Rotor blades continued

 

Alternative method of twisting blades

 

If Builders don't like the idea of steaming try water soaking a 2" wide section of the blades 6" in from the tips gently apply the twisting force and weigh down and pack t/e as above.

 

When dry a little tweaking may be needed ( both methods) Check the amount of twist is sufficient and reasonably equal on each blade then seal with thinned PVA or the sealer of choice.

 

The next job is balancing the blades.