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bob27s -> RE: F-14 propjet engine (11/27/2007 3:59:53 PM)
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quote:
ORIGINAL: mcdonald77
Questions,
I am starting to build a Matt Halton F-14. its the one jet hanger sells for twin edf. The original plans put out by Matt state prop jet. My question is size, I need a lot of punch but with minimal prop lenght. I am still debating it being a pusher or puller. Could the jet .30, or .35 pull or this thing? it should weight around 5-7 pounds and I will have a nice concrete runway. Looking for any advice I can get. The plans are availible free and www.parkjets.com called the matt halton f14.
Jason
Hi Jason......
That F-14 is a fairly large aircraft. I am not sure a 35 would be appropriate if it come in a 7 lbs. At 5 lbs, it might work well.
The Jett BSE35 is the most powerful small-block out there right now. And it is about the same size and weight as the other .32-.35 size engine on th emarket. The jett 35 puts out more power than most .46 engines do.
If you can deal with the size and weight of a larger engine, the Jett SJ-50 or 60LX are a great deal more powerful and worth considering.
I personally prefer front engine arrangements. With a pusher, you have to very carefully consider the fuel system, you have launch/ground rotation issues that drive your prop diameter/landing gear length or launch device (hard to hand launch pushers). Plus with a pusher, you are VERY limited in prop selection, and prop selection is everything when trying to get an aircraft and engine combination to perform its best.
For the .35 you will want to look at 9x5, 9x6 props --- also can consider the 8x7 and 8x8 props, or the racing 8.5x7.25. Key in prop selection is you want the engine turning "over" 17,500 at ground peak rpm. The 9x6 typically will get up to or over 18,000 rpm. So if you decide to go pusher, the APC 9x6P would be a decent choice.
The SJ-50 or 60LX can also utilize the 9" props .... with the same rpm target. Props 9x7, 9x8, and up to a 9x9. For the 60LX I usually recommend the 9x8, or one of the D-1 seriese racing props like a 8.8x8.5
Let me know if you pursue the project !
Bob
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