all is in the tittle
he is an Australian fellow having made monoseaters including wooden rotors .
I had a conversation with him on youtube .. he made me think a lot about my take off technique
dunno if he knows the forum and or Muz
he showed me an incredible video in which a guy takes off really shortly without pre-rotator



what do think of it ?

would it be possible with a metal rotor ..? I think his rotor was made from wood but I am not absolutely sure

Blade profile is what's important not the material of construction

Map out the airfoil shape for performance

hi hillberg,
in fact I was wondering if a heavier rotor was ot more difficult to bring at flight rpm then his wooden rotor ?
you right it is not a question of material
cheers
G

A heavier would only slow acceleration , Wouldn't know about Gyros, Just Helicopters here

Tested QH 50 blades, the later D model blades were 16 lbs and the rest were 60 lbs same exact profile
With the heavier blades I could do hovering autos from 8 feet without touching collective [settle to the ground like a feather]
gentle response in cyclic - flew hands free.

With the light blades it became like an R-22 - quicker rpm loss and no hands free flying - I put my old heavy blades back on.

That takeoff was like Estevons with his KB 2 - impressive

until Ken Brock took his blades back because Estavon didn't finish paying for them...Never saw anyone rush off to the bank so fast, Fun times

The flat bottomed blades were easy to start, they also had a single skin top and bottom, unlike the Benson segmented skins

all of this is really impressive,
as a mater of fact I prefer my heavy blades, they are less reactive but much more forgiving ..
but in a rotor all plays a rôle, placement of the cg on the chord (cord ?), rigidity, twisting etc etc ..
I wonder if it is possible to make a long rotor in wood .. I am afraid it would twist much more..

Yes, wood rotors seem to have wider chord and less length... many have weights added about 3/4 of the way out to give inertia to light blades. Evidently they are very 'springy' and comfortable... a bit like skywheels from what I have heard

Cameron lives a few hours from me... I will meet him one day

Had an old Benson with wood blades and put the blades on a test rig with a small electric motor and balanced them.
Then I got the stupid idea of removing the chord weight that was bolted on at mid span
this was common knowledge with gyros....and helicopters. I wanted to see what they'd do....

And flutter they did with 18" worth of climbing and diving at several times a second. They were slightly coned at 70 rpm and fluttering like mad on steel cheek plates and a steel hub.

It brought me a big smile to see it go Berrrrrrrrrrrtttt. Then I put the chord weights back on.

Cameron and I had an interesting discussion in the comment's bellow a youtube video (calidus non lethal accident)
then we continued our discussion via Email.

he has given me a different perspective about rotor start and take off ...

he reinforced my feelings that the transition btw motorized pre-rotation and auto-rotation had to be smoothed rather then to be forced ...

I was sure that the old rotor management skills were not necessary dated and that pre-rotators had replaced the necessity to learn rotor management ...... but now I am sure that pre-rotating hard, stick fully forward , then accelerating full throttle is a stupidity because the gyro simply ends up behind the power curve forcing the pilot to use a lot of energy and runway distance before he manage to get back the gyro beyond the power curve and take off ..

Fucki hell ... every-time I think that I understand Gyros and rotors someone shows me that gosh I am only an ignorant newbie ...

Cameron is completing the build of a glider so that he can test his new wooden rotors and help newbies ...

an humble, generous, clever man ... do visit him

Giro, I must say I am a bit shocked tonhear you ever sided with the full back rotors and full steam ahead on throttle.
It's a quick way to get wrecked.
As for the short take off in video, some of the older rigs like that light one in the video used the thrust of the propeller to help spin up the blades aonce they got them going fast enough to not flap. I did not think it was that short of a takeoff, as I have a pre rotator that can get about 250 rpm with out trying too hard.
My old Lightning was hand patted, but because of design factors the engine thrust would not help spin blades.
If you want to see some really short take offs, watch guys at el mirage in 15 kt winds like Pete Prentiss...darn near vertical!

Hi Benry ..

Don't be shocked .. it is not good for the heart !

1/ ok a pre-rotator usually only gives one 240 rpm or so ...

2/ the flight rpm of my gyro is 320 rpm at 1 G

3/ lift comes when I have around 45 km/h or airspeed with my rotor at 300 rpm.

So in order to take off as every one does in France (except the pioneers)

on the short grass runways (250 m)

- we align
- we apply full brakes
- we pre- rotate at 240 rpm (engine at 4000 rpm with the 582)
- we put stick fully back (yes yes ...)
- we release the brakes
- and we push gently the throttle passing from to 6200 rpm (with the rotax 582) ... it is a slow motion gesture but it takes max 3/5 seconds
- then the rotor passes from 220 rpm to 280 ... during all this process the gyro is behind the power curve unable to take off
- when the front wheel lifts or gets "light" we push the stick and the 2 mains wheels lifts..
- then we fly over the runway at 1 meter until we get 100 km/h (90 km/h for me with the mono)
- then we pull the stick to commence ascent at 100 km/h (80 for me)


and no body ever flapped his blades doing this ...

and it is strictly impossible to flap your blades because when your rotor is banked 18/20° the drag is so huge that even if you apply full throttle you the air speed will always never exeed 40 km/ h and your rotor is accelerating so quick that flapping is not possible ..

this methos has been invented to simplify this procedure .. for ignorants like me ..

and this video shows that even without any pre-rotator the guy take off nearly as shortly as I am doing with a good pre-rotator ..

here is the story ... but I am A ffrench man ... and it is difficult for me to make me understood in english Bro

That all sounds good.
As I said in the video your thinking he doesnt have a pre rotator. But with a 3 to 5 mph wind and his blades being able to depress enough he can spin them up pretty quick with his prop wash maybe.

what I meant is that he has not a 240 rrpm pre-rotator

he must have had a bit of head wind you are right Benry .. but his take off seems smoother then mines bro..

look the 3 wheels lift at the same time !

maybe does it comes from the fact that his rotor is not fully banked backward during acceleration .. he seems to have a more adequate dosage of rotor incidence .. then my buldoser one ...

what is your take off procedure Bro please ?

With my Gerry Goodwin rotors, I could give them one push from standing with the keel between my legs (on a day with little wind) then sit in the seat and belt on... then start taxying and they would come up to speed fast... if windy, had to give 3 or 4 good pushes...

Started normally, 5- 10 pushes then get in and go, mine would be ready and flying in no time.

Often, I would set off from parking area and be flying while those who started before me were still waffling up and down the taxyway or runway trying to get them to catch on

Once I started using Dragon Wings... different story... had to get them honking as fast as possible and hold your mouth right to get them over the hump.

I always used a 9 degree mast, with 9 degree stick back (so 18 degree total disk angle)... as a cheat... if windy, I could lift the nose wheel with my leg on the ground while sitting stationary and stick back and the rotors would catch fire and go like hell... near vertical takeoff... that was the beauty of the old, high thrustline (low seat) design machines (now all but illegal)

Hi Muz,
thank you for all those details,
could you tell me what was your rotor backward angle when you would taxi please ?
I also would like to know how did you get the "signal" that it was time to apply full power ?
you are also mentionning the HTL configuration of your old gyroplane (thrust line above the center of gravity of the gyro)
it would create a nose down pitch momentum, is that why the guy on the video would take off the 3 wheels at the same time ?
thanks in advance
cheers
G

I knew when the rotors were ready to go when I couldn't see the rotor any more... if you could see the rotor as it passed in front, it was too slow... once they were a blur, you could stick back to get them really going... then ease the stick forward a little to get ground speed then fly off 3 wheels at a time

I never was one to balance on the mains.... the most dangerous time for a gyro is at high speed on the ground... for me, I like 3 wheels on... or 3 wheels off... never high speed on the ground on only 2 mains. I also set my axle position with this in mind. Fixed wings need to balance on the mains (or lift the nose wheel) to change the angle of attack of the wing. We change the angle of attack of our disk with the rotor head Y'all can argue all you like... I don't care

I set up the mast 9 degrees rearward from the keel... the rotor head was at 90 degrees (square to) the mast and the head can go 9 degrees forward and 9 degrees rearward... so, stick full back with 3 wheels on the ground, the rotor disk would have been at about 18 degrees and fully forward would have been zero. The hang test was usually the keel 9 degrees down at the front with stick in the middle


9 was very popular back in the day

I understand things better now . thank you
I have never been taught to do this .. I should try it out.

Sorry Giro, been busy, and the thread title didn't lend itself to checking.

I don't mind balancing on the mains, but I don't do it much anymore.

I doubt you are asking about hand patting procedures, but are more interested in normal takeoffs.
After I am in flight mode, I taxi to a run up area, disengage rotor brake and give the blades a small spin up...Not flight speed! This lets me know theres no strange vibes or bangs and bumps coming. Do engine/control checks. Reengage brake. Make sure at an airport you algin blades fore and aft!!!! If tower tells you to hold short for traffic and they turn at your taxiway, tower will not see your blades.
Once I have the active, I always remind tower it will take a min to spin up...
Go to the intersection (widest part) and turn into wind (almost always 10-15kts from my 2 oclock position) flatten rotor disk with stick full forward. Increase throttle a bit, and engage slowly but smoothly the pre rotator. When blades are spinning as a blur or about 200-220 rpms I smoothly start to bring back the stick. If you have an rpm gauge you will watch the rpms decay immidiately, release brake pressure and begin roll no faster then a man walks and as soon as you see the rom decay reverse and start to build you can go a tiny bit faster, or add more disk back.
Keep doing this until your nose wheel gets light. As soon as the nose wheel is up increase throttle and speed togther. You do not need fast forward motion if the rotors are moving fast.
I like to hop off ground and let rig weathervane 5 feet off ground. Flatten disk and pick up speed in "ground effect" until I am at full speed then climb out.
This is from an airport with a massive runway complex.

Benry,

yep ground effect acceleration is really important in case of an engine failure,

I apply full throttle but I don't accelerate up to my cruise speed (75 mph)

I pull the stick when I get to 55 mph, it both gives me safety in case of engine failure and short take off distance .. for me take off is completed when I pass above 50 ft ..

this method has given me the best results ..

I can't wait to see if I could shorten this distance using a less violent take off method (full pre rotation , stick back and full throttle until the front wheel lifts then stick ahead etc etc )

maybe a milder acceleration with less rotor angle ???

I will check all of this

good day bro

G

Speak of the devil... Cameron has just signed up

So, Welcome Cameron... come join the party

hi
I had told him that we were cool people !
A new kid on the block !
The forum is becoming an Australian gyroplane club hahaha
I hope he will show us Ozzies surfer babes !
welcome aboard
jean michel