Mustang Fever

My Feedback: (2)

Roger that, Stryk. I still have my plans and a lot of wood.

gl2657

I'm glad to see that there is still interest in this plane. I have been flying mine for 6 months now and have pretty much sorted it out.

In Summary.

C of G is absolutly critical, mine is now 1/4inch forward of that indicated on the plan. (Most Forward point). I resolved the pitching by mixing throttle and elevator, took me a bit of time to get it right, the more I moved the C of G forward the the less it was pitching. Take of is the most difficult part, Apply gentle throttle and keep it level with ailerons, let her build up plenty of speed (I only use about 1/2 throttle) and gently ease it into the air.

Keep working at it there a blast to fly.

Strykaas

Many of you guys have skipped the apex, as pictured on Laddie's a/c :



Any good reason for this (apart from ease of build) ?

John Hawkins

My Feedback: (2)

It would be interesting to know if they have any effect on flight. Anybody got wind tunnel results? I used them the first time but am wondering whether to do so in the second edition. Seems like they might have a streamlining affect. I have heard them called strakes.

K.O.

My Feedback: (16)

I now have 7 flights on my Northstar, about 8 water landings and 25 touch and go's. I have a lot of fun with those. After touching the water I keep it on the plane and its off again in no time. After putting 2 holes in the bottom on the 1st flight ( initially covered with 3/4 oz fiber glass) I put a 1/16" plywood on the bottom. Then on the 2nd flight the engine came off in mid air. I was fortunate to land it in the water close to shore with the engine hanging on by the fuel line only. I'd say that was pure luck. After reinstalling the engine with a doubled firewall screwed and epoxyed in, I've had no other mishaps. After only 2 flights it really has some battle scarsthough. After the third flight and a few touch and go's I took it to a flyin last weekend and really had a good time with it. There were 2 other Northstars there. One guys Northstar weighed only 5 1/2 lbs. I don't know how he did it, but it was diffinetly lighter than mine and faster. Mine probably weighs 8 lbs 4 oz dry now after the repairs. I treated myself to one aileron roll. It happened so fast I wasn't sure which side was up after the roll. Scared the tar out of me. I like a lot of control and power but I'm cutting the travel down. When its all said and done I'm glad I built one. Ther're lot of fun to fly. Touch and go's are the best part.
K.O.

mscic-RCU

My Feedback: (6)

Hi K.O. Glad you came last weekend and it was a blast flying with you. I don't know how mine is so light either, except I was really weight conscience when I was building it. The full stall landings are a blast. If you haven't tried one, hold the northstar off as long as you can, then pull full up elevator. It will rise vertically, and ride a cushion of air down to the water. What a blast!! I think one of the things that contributed to the lightness of my model was the engine selection. The only .47 I had available was a GMS. As it turns out, it is very light engine and very powerful.

g_boxwood

Hi guys!

Just received my plans today after a while... I got both the Arrow and the Aquabird which I like best.

Back to the Arrow anyway...

Are there any important mods that have to be taken into serious consideration prior to start building it? This thread turned out quite long so I think a summary could be of help.

Thank you for your help.

Mustang Fever

My Feedback: (2)

Take a look at Greg's last post, just a few up from here. This bird has some serious issues with down pitching under power, and if you don't address them, you'll be picking up pieces.

jrf

My Feedback: (551)

I read that Laddie (the designer) now recommends 2 or 3 degrees of downthrust in the engine to cure the pitch change problem.

Jim

g_boxwood

Thank you!

Any other mod regarding the structure and/or the building?

John Hawkins

My Feedback: (2)

I found that the CG needed to moved ahead. Mine ended up a 1/2" behind the step and was working fine there until I lost it due to flutter. I started a replacement and will incorporate 3º of down thrust and a few detail changes that reflect personal preferences and attempts to control flutter. Flutter occurred during a long very steep full power dive which would be an extreme condition. It probably wouldn't have happened in normal flying.

gl2657

Mine has no construction mods apart from wingtips and a different shaped fin. big thing is to get the C of G forward of that indicated on the plan.its easy done and does not take to much lead in that long nose

Strykaas

Greg, what about an accurate cg measurement ? It is very helpful information here thx

gl2657

I just went and measured it 400mm (15 3/4 inches) from the trailing edge of the wing. 17mm (~3/4 inch) behind the step, 19mm (~3/4 inch in front of the most forward C OF G on the plan. John says his was about 1/2 inch behind the step mine is 3/4 inch. Somewhere in this range will be about right. I initially flew mine at the Mid point of the C of G 50mm (2inches) behind the step, It was flyable but very touchy..Big trick is to get it off the water nice and "Square" after that its a dream

Does this all make sense???

Strykaas

Thank you Greg [sm=thumbup.gif]

simhatus

Hi

I have finally got my arrow flying well, it has an irvine 53 and i left the strakes off.

The only strange thing is it seems to need masses of down elevator as soon as the engine stops to avoid stalling, needs lots of reflex for normal powered flight. i can of course have 2 settings from the tx but this will take some experimentation to get right.

Simon

gl2657

simhatus,

Sounds like your C of G is not right. were is it?

John Hawkins

My Feedback: (2)

My first thought as well.

I have another one flying now with 3ΒΊ down thrust and the CG as discussed in previous posts. Like you say, get it off the water "square" and after that Bob's your uncle. I found that rudder is a real no no on the take off run. Touch it and a wing tip will dig in. Chop and wind add difficulty.

gl2657

John.
I use rudder just to get it going the right way, after that no more (It tracks so well anyway)Nice and gentle on the ailerons just to keep it square...

The weather is getting nice here now so it will be off to the dam and get some flying in..

Cheers

Strykaas

Hi John,

So did it eventually help ? Is the flying difference that big ? Thanks for your answer, a very valuable one since you've tested both configurations

John Hawkins

My Feedback: (2)

The down thrust helps a lot on the take off run. Now I can ease it off the water instead of holding hard up elevator. The nose diving on relaxing the elevator is almost gone. Certainly it is no where as severe as it was. Moving the CG forward of that shown on the plan is essential IMHO for reasonably stable flight. With it set as per plan it is quite a handful. Haven't tried any full power dives to test for flutter. I have some engine and exhaust issues to straighten out first.

I find it easy to snag a wing tip in choppy conditions, particularly if the plane is far away as it is hard to judge roll. I did try some closer in takeoffs but found it dangerous if a tip snagged because even if you shut down the plane may become airborne with little control available. This happened on day one with the new plane and I ended up plonking it into the bush along shore and snapping the pylon at the base. Fortunately it was an easy fix. We almost always have wind and wave so I take it out far enough to leave a good safety margin. Once airborne the plane grooves right along. Landings are not difficult. I doubt if this plane will approach the popularity of the Northstar though.

simhatus

Hi

Can't remember offhand where the cg is i'll let you know.

Simon

Strykaas

Thanks John for your input. Any picture of the new one by chance ?

I think this thread turns out to be a very good help to the next Arrow builders / flyers Thanks to you all !

John Hawkins

My Feedback: (2)

Here's a video a friend shot of the maiden of version II. The camera was a non zooming pocket model so the video suffers but it does show how things went [link=http://rcalbum.machawk.net/video/Arrow_II.wmv]Video of Arrow II[/link]

This is the video from Arrow version I [link=http://rcalbum.machawk.net/video/arrow_1.wmv]Maiden of Arrow I[/link]

My engine isn't turning up to max in version II. Tonight I found a fuel problem and that the spinner (Dave Brown aluminum) was out of balance.

simhatus

Hi

The cg of my arrow is 14 1/4" in front of the leading edge of the wing without fuel

Simon