Spitfire

[Mikerjf]

Jason;

Decided to go with the N20 4/1 with a 4x4 on 8 120mah nimh. Threw everything together and it comes in at 2.8 oz. Hope to get that down to 2.5. The drive runs at 8000 @ .9 A and 32 mph should work OK. Hope to have it flying next week.

Mike

[Jason Nowell]

Cool Mike, I'll go get one of the P-51's and get started so we can trade ideas, sounds like your will be a "Pocket Rocket" pardon the expression :)

Send pics too if you get a chance.

Jason

[Mikerjf]

Jason;

Spitfires done and ready to go. Just waiting on the cells, I thought I ordered them last Sunday but it seems the fax got lost so I don't know when I'm going to get them. With a 30g weight to simulate the battery the all up weight's 2.6 oz. Finally got to fly the Bipe on 6 cells (slowed it down a lot and made it easier to keep up with, might go back to 8 cells when I get the throws right) and if I did the numbers right the Spitfire should fly like the Bipe on 6c, but it'll have to land a little faster. It's actually an easier conversion than the Bipe. I cut the fuse in half from the nose to the rubber band hole (should have stopped 1/4 inch before it, the tails got a little twist in it because of the hole) and mounted everything to the bottom, the top's just a hatch. When I get some pics I'll post them.

Mike

[frankenfoamy]

I converted the ME-109 of the series.
first tried the gws direct drive with a UH-80 prop.
Ran into the prop speed dilemma.

Installed a N20 4:1 and gunther prop 2.1 oz w/o battery.

Reinforced the wing with depron

Flight tests tomorrow

[Twmaster]

When you mention 'series' do you mean the planes from flying styro?

Mike N

[Mikerjf]

Frankenfoamy;

Don't think you'll be too happy with the Gunther prop (could be wrong). I did the numbers and you need just over 30 mph pitch speed. I've got the GWS 4.5x4 trimmed to 4x4 on the N20 @ 4/1. It gets 8000 on an 8c nimh pack. An extra bonus is that the Funcraft spinner is a push on fit with the GWS prop hub.

Mike

[frankenfoamy]

Not flying styro. funcraft 14" wing

Chuck from thousand oaks used a 4:1 and gunther on the Mustang in the funcraft series. Basically the same plane. It really scoots. BTW he uses magnets to hold the wing on.
Iwas able to manage getting the gearbox inside the fuselage.

Unfortuantely, I think I got a little glue on the spur gear. Hope I can work it off.

[Mikerjf]

What battery pack are you using with the N20 4/1 and Gunther prop?

Mike

[frankenfoamy]

7 cell 120 mah pack from John Worth.
Have not flown the new set up yet

[frankenfoamy]

Flight report
Basically it was a powered glide.
I question my thrust line (to0 much)
It took full right aileron to compensate for torque.
As you can see I have right side thrust.
What do you think of the down thrust too much?

[Mikerjf]

Down and right will kill you on these things, learned that with my Sporty. Had it S280 direct drive with factory down and right and it flew fair, took out the down and right and it flew great (same holds for the S300 geared. Mines got 0 down and a hair of right I didn't plan on (bad eyes,big thumbs). The Gunther prop's going to get you a lot of thrust (and a lot of torque) but not enough pitch speed (hence the powered glide) at 9 to 11 oz/sq ft it needs 30 to 40 mph. Wish I could get my order from RRC, no cells, no fly. I'm dying to try this thing out.

Mike

[cartwrigh]

I have no scientific basis for my idea but we are used to having the prop and engine/motor turning in the same direction but I believe that geared Electrics with the rotation of the prop and power source in opposite directions cancels a lot of the P effect therefore reducing or eliminating the need for offset thrust.

[frankenfoamy]

P effect is a prop angle of attack phenomena

I am using a lot of aileron and built in right rudder to cancel the left pull. I can not rule out that the wings are not at different angles of attack. I reinforced them with depron to stiffen and even out the warpage.

[Mikerjf]

Finally had what resembled a flight. The first two attempts produced a climb ending in a stall/roll to the left. The third try I moved the cg back and gave it a pretty good heave and it actually exhibited flight characteristics. Had about 1/8" on the ailerons and 3/16 on the elevator (way too much) so it was way too whippy. The N20 4/1 with the GWS 4x4 on 8c seems to provide enough speed/thrust, but at 2.7 oz. (11 oz/sq ft wing loading) it has to be kept fast. If the weight could be cut down 1/4 to 1/2 oz it should fly well. Anybody know of a 9.6v battery pack lighter than a 120mah nimh with 50-70 mah?

Mike

[Mikerjf]

Haven't totally given up on this thing yet, but I just noticed some free flight warbirds available from Hobbico which have 18.5 to 20" spans, just ordered a few, should work out much better with about 60 sq in of wing.

[Mikerjf]

Practicing posting pics