Crash-RCU

Ok I have a question. I have a 45 size ducted fan and engine not doing anything and was wondering if I bashed an Arrow and mounted the fan on it instead of a engine and prop if it would get up on step and fly off water. Club member has a lazer cut short kit and plans he is trying to sell me .So will it ROW that is the question, so far answers from those that I have asked run 50 50 yes and know

JimCasey

My Feedback: (1)

It might, or it might not. :-)

What I worry about is the ducted fan being heavier than a motor and prop combination. If you hang a few extra ounces waaay back on the tail and have to compensate with three bricks in the nose to get it balanced, then it will weigh several ounces and three bricks too much. That'll generally have undesirable consequences to the a/c performance. If your DF is no heavier than a motor/nonducted prop combination, the Arrow is designed to need less weight to balance than the Northstar. Pretty much the criterion that determines how much thrust you need to take off is the airplane weight. Keep it light and get it to pop up on the step. Once you're on step, the plane should accelerate easily to takeoff speed.

If you have ever water-skiied, you know how hard the rope has to pull to get you up on the skis, but once you're skiing you can one-hand it. Same thing with floatplanes.

Crash-RCU

Jim thanks for the reply. Of the people I have asked about this you are the only one that has took in to consideration and that includes me, the fact that I will need three bricks in the nose. The fan, motor and pipe do weight more than engine prop combo. Now that you shed light on that problem, I believe there will be to much weight to the rear to balance out, without the plane weighing ten pounds.Now if only I could figure out a design that would work, guess I'll keep thinking about it. Thanx

Wayne22

My Feedback: (2)

Jim..I always read your educated replies with interest......this one is one of your best

jrf

My Feedback: (551)

Some years ago, one of the Lake Havasu modelers mounted a 65 (?) DF on a Northstar. He put the engine on top of the fuselage right above the CG and eliminated most or all of the nose weight. Unfortunately, the ducting for the fan was so close to the water he had a terrible time getting it up on the step before water splashed in and broke the fan. It did fly though, and it was FAST!

Jim

Crash-RCU

Jim, Thanks for the input. I guess I need to look at the plans again and see if I could move the fan foward to eliminate having to add a ton of weight to balance. Still seems like an interesting project, but if there is only a small chance of success don't really want to tackle it.

Newc

Maybe you could contact the designer, Laddie Mikulasko? I don't have a contact address for him, but know he's in the Toronto, Ontario, Canada area.

JimCasey

My Feedback: (1)

I can find no history that Laddie has posted in this forum.

Strykaas

D/F arrow :

http://image.rcuniverse.com/forum/up...10/Db85587.jpg

Thread :

http://www.rcuniverse.com/forum/m_15...anchor/tm.htm#

Post #310

JimCasey

My Feedback: (1)

Just a general word of advice:

Never say the word "Arrow" within earshot of a Canadian without using the most reverential and respectful tone possible.

Newc

OK, I'll bite. Why?

JimCasey

My Feedback: (1)

The Avro arrow was a supersonic, delta-winged interceptor developed in the late 50s in Canada. Pressure from the Eisenhower administration got the project shelved and the Canandians adopted the CF-102 instead. In fact the Arrow would outperform the F102 and probably the F106 in most of its flight envelope. The Arrow was a great source of national pride for Canadians and they are still upset.
So when Laddie built a delta-winged model and named it the Arrow, he got a free pass to the Canadian hall of Heroes, Grade Eh!.

You won't find a website like this for the Northrop Scorpion:

http://archives.cbc.ca/IDD-1-75-275/...gy/avro_arrow/