Enough power ?

[fun-flyer]

I have a Rotax 503 DCDI with e-box 2.56:1 or 2.62:1 ratio etc. The prop is a Warp Dive three blade 64". I'm building a single place gyro and currently the frame weight is about 110 #'s. I still need to get the pre-rotator and control stick installed which will add another 20 #'s. The engine is supposed to be 52-55 h.p I believe. I weigh in at 240 #'s and would like an opinion if this engine will produce enough power to fly. The blades are 25 foot Dragon wings. I'm sure there is probably more info needed here so let me know what that is and I'll answer the best I can.
Grego

[Brent_Brown]

It should fly but I think you will be at full power most or all the time. Make sure you get 6400 RPM on the ground to get the best climb out. Trees get big fast.

[gyropilot]

Grego,

I fly a GyroBee with a 503, 3-blade 60" Ivoprop and 23 foot Dragon Wings. The all up flying weight is about 540 pounds. It has plenty of power at the altitudes I normally fly from sea level to 3000' MSL. Climb rate at sea level on a hot summer day is about 500 fpm at 45 mph indicated.

To be sure your gyro will never be a rocket ship, but if you can keep your all up flying weight to 545 pounds or less, with those 25 foot Dragon Wings you're going to have adequate performance to enjoy flying.

One thing that comes to mind though... With that large of a diameter prop and 3-blades, I'm betting your prop pitch will have to be quite low in order to achieve anything close to redline at your climb airspeed. You'll have a "climb prop" and this both good and bad. It should give you great climb performance, but your top airspeed will suffer and possibly your cruise rpm will be higher than desirable causing higher fuel consumption. However, if you don't need to keep up with RAF's and Dominators and don't mind cruising at a lower airspeed (45-50 mph is very comfortable in terms of air pressure on your body), I'd opt for better climb anyway.

Anyway, later on once you get comfortable with your gyro you could experiment with only 2 blades on that same 64" Warp drive prop. The pitch would be significantly higher, the climb performance might still be adequate, and you might get better fuel economy.

Fly safe,

John L.

[fun-flyer]

John
I also have a Rotax 618 and am considering taking the drive from the 503 and putting it on the 618. It has the lower ratio I want. That would solve any power issues and let me keep up with Scott and Danny. Scott flys a Dominator with a 618 and Danny flies a.. a.. a.. a.. a,,, okay I can't remember the name right now but both will do a good 70 MPH cruise with tops around 90. I don't have to keep up but it would be nice to be able to. I'll try and inclose a photo in this reply of my ship in it's current state. The engine on it now is the 618. The reason I may use the 503 is because it would be easier to install right now. I'll be buying some more tubing next week and may build a gyro bee to use it on instead since they are a lighter frame.

One other thing (if you don't mind). What is your weight :)

Okay more later I've gotta get some chores done.
Grego

[Adam H]

fun flyer, what kind of machine is that?

[fun-flyer]

Adam,
It's a combo of Dominator, Air Command and Mad Max. I looked at all the different ships and picked out what I liked best about them, then added my own ideas and this is what came out. I had it parked next to a Dominator frame in my gargage and a friend came over to look at them. He said the Dominator looked like an F-14 Tomcat and mine was more like an A-10 Warthog. Oddly enough both frames without the engine and pretty close to the same configuration came in within 5 pounds of each other. I did add a folding mast I dreamed up so it would fit through my garage door. I hope to have it ready for test flying by late Fall. It's just to dang hot and muggy here in the evenings to work out in the garage and I've had a problem saying no when friends who are getting out of flying want to sell there machine/projects. I'm getting pretty gyro poor right now. My plan is to finish building them out and sell. Maybe one day I'll work up enough cash to buy a Sparrow Hawk and not have to give up my first child :)

Greg Massey
President
PRA CHapter 62
Houston, TX

[GyroRon]

Greg, short anwser to your question is no. Use the 618 and you will be happy, use the 503 and you will be sad.

Did you ever sell that EAA bi-plane?

[gyropilot]

John

One other thing (if you don't mind). What is your weight :)Grego,

I weigh about 170 with all my flight gear and helmet on. My gyro weighs about 305 empty, and I carry 10 gallons of fuel.

Top speed at full power on my Bee is about 70. Max range seems to be about 50 mph, so that's what I cruise at most of the time. My 503's been averaging about 4 gph at that speed.

I gave up long ago trying to keep up with the RAF's around here. I just go my own speed and get where I'm going when *I* want to.

Good luck wth your project.

John L.

[gyroman]

Yea Grego, use the 618 that way you can give me the 503 to throw on my gyro :D

The gyro looks great. Keep up the good work!!

[fun-flyer]

Greg, short anwser to your question is no. Use the 618 and you will be happy, use the 503 and you will be sad.

Did you ever sell that EAA bi-plane?


Hey Ron,
Yes I sold it last year to a Rich Sampson in Massachusetts. He's doing a recover and painting it black from what he told me a few months ago. I don't know why he wanted to recover. I think he just wanted to look inside. The cover was out on in 1999 so it wasn't old by no means.
Greg

[fun-flyer]

Okay all I did a preliminary all up weight and it will come in near 700 #'s flying weight. SO it looks like the 618 will be my engine choice. Now what to do with the 503. Maybe build a Gyro Bee :)
Grego