P-70 Night Fighter

Ed Kettler · Post by **Ed Kettler** » Mon Jan 28, 2008 10:08 pm

Sunday marked the maiden flight for the latest twin in the 2548 fleet: a Douglas P-70 night fighter. Scott Stockwell cut the wings, I did most of the building and then turned it over to Cash Hargett for final assembly and covering.

Until we get the RCCA Gallery moved, the photos are over here in the RC Groups: http://www.rcgroups.com/forums/showthre ... ost9035378

The weight came out a little heavy, but the performance was good at 17.5K; can't wait for more flights and getting the revs up to 18.5K!! Only got one test flight in yesterday due to the engines propensity to spit muffler bolts. I replaced the 2.5mm Phillips head bolts with 4-40 socket heads. All it takes is about 10 minutes per engine with a 4-40 tap.

Scott "The Catapult" Stockwell did the initial launch with Colonel Hargett on the sticks while I played combat photographer. Somewhat surprising for all of us was the sustained 30 degree climb which got the big bird up to test altitude quickly. The only bad thing to report about the first flight was that Cash had such a great time with it that he hogged all of the flight time!

Thanks to Scott and Cash for all of their help. I'll post more pictures after subsequent flight tests.

Rabbit Leader · Post by **Rabbit Leader** » Mon Jan 28, 2008 10:17 pm

30 degree climb? Jeez, I felt it was more like 60, or maybe I was just busy adding trim...[:D]

Gonna keep this short, but the doggone thing flies MUCH better than either Ed or I expected...he's right I was having WAY too much fun, when I landed, Ed went over and released the bladder pressure and all he got was a little spit, hardly any fuel left at all.

Good roll rate, decent speed, good climb, turns better than expected...if it was a bit lighter some of you boys would be in trouble. As it sits right now, I still feel that it will be competitive in 2548 with a determined pilot on the sticks it has NO bad habits whatsoever. I guess Ed and I worked the bad juju out of it..[:D]

sgilkey · Post by **sgilkey** » Tue Jan 29, 2008 8:34 am

you guys are much better men than I! I don't know HOW you even CONSIDER combatting with planes like that, that looks like a lot of work to build! Looks great in the photos, nice job!

Ed Kettler · Post by **Ed Kettler** » Tue Jan 29, 2008 1:08 pm

The sound of synchronized twins screaming in unison is intoxicating[:)]

All I have to do now is engineer the matrix so I don't fly in the same heats as Cash[:D]

drewjet · Post by **drewjet** » Tue Jan 29, 2008 2:38 pm

Looks sweeeeeeet Ed

o1moregil · Post by **o1moregil** » Tue Jan 29, 2008 4:02 pm

Ed very nice twin!! is it packing tape for covering?

Rabbit Leader · Post by **Rabbit Leader** » Tue Jan 29, 2008 10:10 pm

Gil, she's covered in Coverite Black Baron, a little bit of Econocote in the real twisty bendy areas, and the canopy is regular monokote with Black Baron film, decals are GWS.

It's really not my best covering job, but I think it turned out okay...looks real purty in the air though..

Cash

grasshpr · Post by **grasshpr** » Wed Jan 30, 2008 11:35 am

Very nice Ed, Cash, there's nothing like a twin! That's a nicely put together design, looks good, nice lines. I think you'll appreciate the 18.5k when competing against good singles. If your motors will spool up that much, it's easier said than done, I think.

Now you've shamed me into getting back to work on refining my twin project(s). My 2548 efforts lately have been prototyping a Ki-43 Oscar. Almost finished, test flight in a week or so. Then I can revisit the twin mustang design that you saw at last years LSN. At 5 lbs. it really has to go on a diet, and make closer to 18.5 to run with the big dogs! I have a second twin project from the list in the back of my cobweb filled mind, but have yet to draw anything up.

Rabbit Leader · Post by **Rabbit Leader** » Wed Jan 30, 2008 11:48 am

Hey Chris,thanks for the kind words. I have a 3696 KI43 that flies beautifully, and I've had the -43 on my mind for 2548 for some time, just haven't had a chance to build one. I was wondering why no one else has thought of one, as it has great wing and tail area, good moments and a nice slim rear fuse that will probably go a long way in keeping it from being tail heavy. When you finish it, I'm sure it will turn out to be a real pretty nice flying bird.

Another plane that I think would make a real nice plane for either 2548 or 3696 is the KI-84, don't know why it's not been built, either. Guess scale combat pilots are a rare breed nowadays, it's a pity..
Cash

Rabbit Leader · Post by **Rabbit Leader** » Wed Jan 30, 2008 11:52 am

Y'know, meebbe I can get a 2548 Buffalo going..worth a shot..Ed will like it[:p]

Cash

Bo_Connolly · Post by **Bo_Connolly** » Sat Feb 02, 2008 10:08 pm

Very Nice Work Guys !!!

Really Nice Aircraft !!!

I'm gradually getting my shop running again and I'm definitely planning on joining in the Scale 2548 Fun up in Dallas...

Once I crack the Open B nut, I'm gunna roll into Scale stuff more...

Ya'll Take Care,

Ed Kettler · Post by **Ed Kettler** » Sun Feb 24, 2008 8:18 pm

After replacing the muffler screws with 4-40 hex head bolts, she sure is a sweet running beast now. We put two flights on her today, and I was able to pry the transmitter out of Cash's hands to get most of the flying in today. The LAs were taching 18.5K (thanks a bunch Grasshopper!!!!) and boy she is eager to get up and go with the extra 1K per side. The extra grunt will make her competitive, but I don't think that a great running single will have to worry about getting overhauled by the "Black Beauty", as most of the improvement was in climb performance.

Thanks to Scott, JP and Cash for helping out today! Look for Black Beauty at LSN 2008

Ed Kettler · Post by **Ed Kettler** » Sat Sep 20, 2008 9:37 pm

Today marked the maiden flight of the electric version of the P-70, done up as an RAF Havoc night fighter/intruder. The setup is basically two of Lee's SSC motor/ESCs driven off a single 5000 mah 4S Lipo. All up weight is ~5.25 pounds with battery, so it is not a light weight plane, and is about a pound heavier than its glow brother.

The first flight was performed by Lee Liddle, and was used to establish flight trims and get to know the plane. We did uncover one problem: the leading edge covering on the right wing was pulling away in the prop blast at 18,500 rpm, so we ended the flight early.

The second flight was uneventful, and we will do some rework on the horizontal stab to reinforce it, look at the CG (maybe a bit aft), and improve the cooling. Overall, very sucessful.

Thanks Lee for doing the first flight, and thanks to Scott Stockwell for kitting the plane and helping me with the wiring.

Ed

draftman1 · Post by **draftman1** » Sat Sep 20, 2008 11:28 pm

thats a very nice looking plane. I like that alot. you did a good job!!

Ed Kettler · Post by **Ed Kettler** » Sun Sep 21, 2008 9:50 am

Thanks for the kind words, draftman1. We will probably scale this one up 50% to 90" and put retracts on it so folks have a nice electric IMAA bird. We will use a different motor setup as this bird is very overpowered for scale, probably geared brushless and three blade props.

After two flights, the 5000 MAH 4S took 4818 mah in recharge, and the starting voltage before recharging was 3.55 to 3.57 volts per cell, so this battery may be under rated.

After doing the twin glow engine dance with the black P-70, this setup is <b>sweet</b>! Plenty of power, simplicity of operation, no slimy mess, no clamps, no broken fuel bladders. We did dial down the ATV to get within the 18.5 limits, so this setup has plenty of power. If you like twins, this is a great flying plane. We will post updates on kitting the plane for 2548.