Scenario

17 pound Wildhare Edge, DA 50 engine, which pitch prop would give more thrust for hovering and pull out?

22-8 23-8 24-8 22-10 ???????

I have own BME and ZDZ engines whenever I have this type of questions I use this link to compare different trust, no all the brands are listed up:

http://freespace.virgin.net/barry.ho...e/goodies.html

Menz-S 22x8 works very well with the DA-50. Great all around performance.

I have heard that a 24-8 is a better 3D prop? I have 4 gallons thru the DA 50 and beginning to use Amsoil 100 to 1. Do you think I will need to tweak the needles?

We, too, have a 17 lb Wild Hare Edge. DA50 with Slimline pitts. I have tried all the props listed and give you my opinion. Strickly 3-d type flying

22x8 high rpm figures, makes a lot of noise, better off putting more load on engine, I don't feel you are taking full advantage of engine with this prop.

22x10 assuming good quality prop, such as 3-w, Menz, etc. very good combo on plane. good hot weather prop because it is less load, but not much, than the 24x8, thrust generated by the 22x10 is not as great as the 24x8, but difference in pitch and spool up time makes it a very comparable prop.

23x8 only prop in this size I am aware of is the mejzlik and msc. MSC is a lot of load on the engine. Mez is the best all around prop, quieter than the rest, great pull. Only downfall is weight of this prop vs. wood, which has a pretty big effect on spool up, as in hover pull out.

24x8 high quality such as Menz or NX is a great 3-d prop in cooler weather, or if using other exhaust set-up. With hot, humid weather tune on engine (with pitts exhaust) we couldn't get 6000 rpm and engine sounded loaded.

For 3-d, I prefer the 24x8 if you can get the rpms up to 6300 or so, otherwise the 22x10.

What RPMs did you get with 23x8 props?

About 6300-6400 on the Mejz, if I remember correctly, spool up was the issue. Actually flew that prop quiet awhile until trying NX 24x8.

at 17 lbs with a 50 and an incowl muffler --you are about maxed out on thrust for hover
prove it to yourself
forget charts - forget what someone claims is ideal - hook a good spring scale to model around the stab--use a padded soft rope
have someone stand with legs holding model along stabs
rev engine and gently pull scale till the model move back a little from the helpers legs
I bet you have trouble getting 20 lbs actual full throttle thrust
Best prop will likely be a 22x8 -perhaps a Mejzlic
Let me know what actual thrust you get ..
If you are not gettin a solid 20 lbs - your hover ability will be very chancy.
Ideally -you would get 25 lbs or more.--for a 17 lb model
PS don't run the engine lean and for long runs on the groung doing these tests -it just gets it hot and the power will lessen.

Dick

Have you already tried the pull test for the static thrust 22-8 VS 24-8? I was just going off a prior post in the giant scale forum concerning the DA 50. I have just started on my 4 gallon of fuel (AMSOIL 100 to 1) but now it seems like my midrange is rich, any ideas. By the way I,m running a MSC 22-8 wooden prop. (You know always wanting something better).