How much is enough ?

[groundhog]

For the typical tandem,what is a good horsepower minimum?Generally here is 1000' and 90 degree days are rare but possible.
What is the 2.0 soob rated at?

[scottessex]

All I can say is that John Stevens dominator flys great 2 up, Empty weight is 400lb, 73HP, loaded is about 900lb gross, so that would be...12.3 lbs per HP.

My single place soma is about 560 gross at 65 rated HP....8.6 lbs per HP

But the dominator seems to have more power and flys faster than mine.

I guess the blade size has alot to do with it, or I just have a turd!

[ben]

scott

might the pod out front have anything to do with it ???

[ben]

ahhhhhhhhhhhh man no pod dang lol lol lol

[scottessex]

John just has a rocket! Dang aircraft will lift it's own weight in payload, (passengers) and still fly good!

[gyromike]

Scott,

What size prop did ya'll mount on John's machine?

[scottessex]

Mike, Prop is a 72" kievprop. The 618 is definitly moving alot more air than my 60".

So I guess the whole power to weight thing depends on alot of factors.

[ben]

scott

i think thats what we found out at bdays 2005 when we were doing the thrust test on everyone. it seemed that every one swinging a larger prop was pulling more. around here it seems that everyone swings a 60" prop? thats one reason i'm putting a 72"prop on my ea81 and according to the birdy and butchS and the boys they swing as big as 76" on a ea81.

also most of them swing a 2.5 to 1 on a gear boxes we run 2.1 to 1 on your subbies. don't know maybe bigger is better lol lol lol

[gyromike]

75hp...72" prop........

Mmmmmmmm, power!
Sounds like the right recipe for a single place.

[CLS447]

Scott, what is your Disc loading compared to John's ?

[ben]

ok guys

lets talk turkey !!!!!! whats more important when figureing what a gyro needs to fly?????? auw, disc loading , hp to weight ratio, the size of the prop, rotor blade size, or just plain hp????

this should be fun

[scottessex]

My disc loading is about 1.4 lbsqft and Johns is about 1.2, but He should be around 1.4 2 up.

Ben I think that combination of prop size rotor size have alot to do with performance as well as Lb per HP.

[ben]

hey guys anyone else??????

[Screw]

Screw-In

Ben,

You hit it on the head. It's all of the above.

From a lightwieght a standpoint, if you build you gyro to be as light as possible, you reduce you AUW.

When selecting an engine, go with something that has a good or great power to wieght ratio. Reliabuility is a factor also.

While building, insure that you can swing as large a prop as possible and go with that prop.

Once you have an established AUW (Which you can't until your done building) go with the reccomended blade size from the manufacturer.

In my case, Ernie said to me one day he used to build 2 place machines that came in between 375-400lbs with a Rotax 618. He quite making them because Rotax quit making the motors. The Rotax 618 was the highest power to wieght ratio engine they ever built.

You don't have to be a rocket scientist to figure out that a 400lbs machine and a 73hp engine will fly fine, but the question is....."Will it fly two people?" The answer is yes.

It didn't dawn on me at the time, but most people flying two place machines with Rotax engine are flying the 80hp 912. The 912 is a much heavier engine than the 618 which apparently makes up for the 8hp differance.

As is with everything with flying there is a cost. I'm using 27' DW, and my disc loading is light enough (solo) to scare me on an 80 degree day. 2 up, I'm fine. This winter I'll probably have to add wieght or reduce my blade size. If I reduce my blade size, I won't be able fly 2 up very well.

Lightwieght props spin up great, but are fragile. Warp drive are indistructable, but heavy. Ivo are easy to adjust, faily light and durable.

It's a combo thing Ben.

Screw-Out

[ben]

hey john

just got off the phone with scott, what we need as home builders are numbers.

for example: you and phil both 618's phil has a 60" prop you have a 72" prop
now i dont know the make of phils prop but the different the make shouldn't make as big a differents as the size would. it would be great if you and phil over at scotts would do a thrust test to get an idea on how much more thurst you get being 12 bigger in dia.