Spacewalker first attempt.
 

http://www.netlabs.net/hp/soarrich/gyroreadytofly.jpg

The weather was perfect for a test flight today.

http://www.netlabs.net/hp/soarrich/modrtm.jpg

I found that I had to cut the front of the rotor tilt mechanism away to clear the locking nuts for the rotor attachment bolts.

I took the Spacewalker out onto the runway and set the Co-Pilot. I'm not sure it was working properly, but I think it was. While holding the gyro up so the Co-Pilot could see the horizon, the blades started to speed up pretty well, maybe 500 rpm, I thought about trying a handlaunch, naw it's 10 pounds has an 80" rotor, and I don't want to get whacked with the blades. I didn't see anyone around that I thought was dumb enough to try it, so I went for the ROG.

The wind was prefect, a nice 7-10 mph out of the north so it was very smooth air. At our field if the wind comes from the east or south we get lots of rotor off the trees making takeoffs and landing dicey at times. I gave it throttle and it gather speed, after about 25 feet the rotor started to speed up, at 50 feet it was going pretty good. I remember talking with someone in Florida and they said once the rotor is coming up to speed to raise the tail and let it run tail up a little before giving up to rotate of the ground so I did. The rotor hit the stab, and flew off landing unharmed 10 feet away. The gyro tipped over broke a rudder hinge and broke the prop, but otherwise in good shape. A pretty mild crash, but a crash just the same.

I wanted to have a .mpg of the "flight", but my flying buddy Charlie and I were so focused on the gyro we forgot about pictures. Below is were the rotor struck the stab, a little CA and it'll be fixed.

http://www.netlabs.net/hp/soarrich/dtail.jpg

A post crash look revealed that the rotor axle shaft had pulled out of the rotor tilt mechanism. Which came first the pull out or the rotor strike? I don't know. One of the guys watching said as the gyro gained speed the blades seemed to tilt back, the front going up, which I would expect, but the back going down, which I wouldn't expect. I would think the back would go up also to form the coning angle.

Tomorrow I think I'll make a new taller rotor axle.

I'll mount the rotor at less of a tilt back. I tried to make it about 10* , but on subsequent measuring it looked more like 12*.

I'll take some of the "aileron" throw out, I've got the rotor able to tilt 20* each side, which looks like a lot.

Spacewalker first attempt.
 

Hi Rich,

Sorry about the crash. Just my opinion, but I would guess that the rotor shaft pulled out when the blade hit the stab. If you are using the SG6042 blade profile, 5 to 6 degrees of rotor head incidence is all that you need. Other blade profiles do require more incidence. My largest gyro weighs 5 1/2 lbs and the blades are only 23" long and it will lift straight up in a 7 mph wind. Based on the size of your blades, I suspect with 10 degrees of incidence, the rotors would pull the nose up and over on it's back so watch the throttle real close on your next attempt. Assuming that you have the hang angle correct, less incidence is better. The worst thing that can happen is, the rotors don't spin up. Too much incidence and you get rotor strikes or it rolls over on it's back.

Hang in there and better luck on the next attempt.

Phil

Spacewalker first attempt.
 

Hello Rich...

Sorry to hear about the tail strike. Here's a suggestion:
Since you have already held the plane while the rotors spun up, how about doing it again and noting whether the plane wants to tilt one way or the other, whether it feels like it wants to fly out of your hand. While doing this, it is possible to adjust trim settings so that it feels as if it wants to fly straight and level, etc.

I would also agree with Phil that 20 degrees of side tilt is probably a lot more than needed. Also the tilt back probably should be reduced to around 5 degrees.

Judging from the photo you included before the flight, it appears that the rotor mast is plenty high. Adding more height, will simply add to the "pitch-up" tendency. Making adjustments to the tilt-back is easier.

The fact that you noticed the front of the rotor tipped up when you started to taxi fast suggests that the high tilt back put pressure on the blades at the front causing them to be "blown" upward. Which then suggests that the rotor really wasn't up to speed yet...not enough centrifugal foce to keep them in a flat plane.

Hope all these suggestions don't seem like "preaching". It's so much easier to armchair quarterback than actually be doing it! <G>

Anyway, it sounds as if you are pretty close to success. The plane sure looks good.

Bill

Spacewalker first attempt.
 

Phil & Bill

Thanks for the advice, it's need and appreciated.

I'll set tilt back to 5*, and cut the tilt to 10* and try again tomorrow. The hang angle looks like this:


.http://netlabs.net/hp/soarrich/hangangle.jpg



I'll do the trim test also this time.

Hopefully I'll remember to get my flying buddy to .mpg it

Spacewalker first attempt.
 

Hi Rich,

Just to add a little more to my earlier comment. I can't stress enough the lifting capability of the SG6042 profile. With a 7 to 10 mph wind the rotors should lift the tail within just a few feet. I have now flown my 5.5 lb gyro with 4 different blade designs. With a size 72 Saito engine I have to use full down elevator to hold the gyro level at full throttle. With 6 degrees of incidence in the rotors and at full throttle and down elevator, the blades in the front are tilting up to 30 or 40 degrees. The first time that I saw that I though the rotor hub was coming apart. However, the other blade profiles only tilt up slightly under the same conditions.

Hope that helps as you are going to get a lot of lift with that size rotor. Your hang angle looks good.

Phil

Spacewalker first attempt.
 

Hi Rich,
Maybe another 2 cents worth will be of interest.
Know this, the airstream force the rotor sees is of unbelieveable
magnitude,if you saw the rotor tilted back you know what it is.
The force is so great that on a smaller Giro it just tears up normal linkages, that is on the pitch mechanizm. For me 4-40
clevis couplers and .078 push rods crumpled.
Finally 3/32 push rods and 6/32 steel couplers have been safe.
I felt a safer test than flying had to be found, turned out to be
real simple. I attached the Giro in flight attitude to the hood of my car with rubber bands and wire hooks.
Turned out to be a great learning tool as well as saving several
rebuilds. Bottom line is if all works properly on car tunnel it also
will in air,
Flight rotor speed seems to come at about 15 mph, at 20 there
is singing! Be cautious with that big rotor!
Good luck!

Hal deBolt

Two Cents Worth
 

Rich

Since everyone else has gotten their 2 ecnts worth in I might as well bore you as well.

I also noticed that everyone seems to be giving you advice regarding small rotor models. Bigger is better but you cant build a large rotor model using small rotor technology. They just do not act the same in practice.

I noticed from your pic viewed from the side that before the fateful flight that you had precious little tail clearnce,,,,,This is not a good thing......and that your blades were drooping alot....
How thick is your rotor hub...??? Mine is 1/8 thick fiberglass and also have some 9 inches worth of tail clearance that your model does not have....

You have been advised to hold the model and attempt to get the rotor in auto rotation....If you do this it will pull you backwards during the process...This works for small models but apperently I am the only one who has large rotor experience aside from Tillson that dares to speak up.....

Set the tilt at zero degree's.

Give the rotor a good flip and let it accelerate.

Increase the power gradually as rotor rpm increases to hold the model from drifting backwards.

Hold in fulldown elevator, this will garantee you will not flip over backwards.

Continue to increase power and gain some forward motion.

There will come a time during this process that the rotor rpm will increase to the point that the model will cease all forward motion. Compensate with increased power while releasing some down elevator.

The rotor will increase its rpm to the point of going into full auto. At this point the tail of the model will rise all by its self.

This is your signal that the model is ready to fly. Increase power a little more and the model will rise all by itself.....

Have a nice flight....Thats all there is too it....


Rick

Spacewalker first attempt.
 

Rick, again,
Take offs, I believe I went into what is envolved with a post for
another modeler, so won't repeat.
Take offs can be simplistic, the actual take off no different from
an airplane plus 100% fool proof baring any stupidity!
But some advance doings are required
Will describe my way, but know I use 60" rotors and that seems
the limit for the average man's arm.
You need a prop spinner om the blade hanger, About 3 ft. of strong string tied to the tail wheel and a drill motor capable of at
least 500 rpm, my B&D is rated 700.
Proceedure goes like this; you need an assistant, with experience it can go solo. With the engine running the pilot stands on the string. the assistant winds the rotor up with the drill motor as this is happening the pilot gives full power.
Once the rotor reachs maximum RPM the drill is removed and the
pilot assures he is ready and steps off the string.
When released the rotor is very near lift off RPM and with full power acceleration is quick so flight RPM comes soon.
Neutral elevator seems fine but even some up when rolling does
well,
90% of the time the pilot does nothing but watch, otherwise
maybe a touch of rudder if a wind gust comes along
With the larger rotor there is a physical problem but suspect an
extension could be added to the drill handle to solve that.
With all the advise your bill will get extensive, so you better have
fun with all this!
Good luck,

Hal deBolt

Spacewalker first attempt.
 

I'm taking all the advice in, thanks guys.
I can't talk now, but here's a few pictures.
The first is some added bracing to the pylon:

http://netlabs.net/hp/soarrich/newbracing.jpg

The next two are just of the rotors fold back for carrier storage, in case the Navy is interested in a full scale version. :D
http://netlabs.net/hp/soarrich/fbb.jpg

http://netlabs.net/hp/soarrich/fbb2.jpg

My buddy Charlie put a tack on the blades today, in 5 mph of wind the blades tacked at 380 rpm, you should have seen them in 20 mph wind. My new RX lost the throttle channel, so I couldn't fly today, trying again tomorrow.

Spacewalker first attempt.
 

I just did the math 380 rpm on a 80" rotor puts the tips at 90 mph, 1140 rpm gets you 271 mph. I'm getting nervous!

BTW, I changed the tiltback from 12*, (tried for 10*, but got 12* somehow.), to 7*. Now I wish I had maded it even less, too little seems to give you an RC car, too much a pile of balsa, just right an autogyro? I'm starting to feel like Goldylocks.

Spacewalker first attempt.
 

But Rich, your story is much more interesting! In fact it's much better than the day-time soaps! <G>

Bill