Posts: 216
Joined: 11/14/2005 From: Frisco, TX, USA Status: offline
I know a guy that had the 200 twin in a GS World Models P-51. I never saw it fly. He couldn't keep both cylinders lit for some reason. He was not happy with it. Ended up selling it and the plane. I would guess it would sound great, but perform less than the single 180???
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Joined: 1/1/2006 From: Fort Collins,
CO, USA Status: offline
Twin cylinder glow motors take more time to break in, but once done, the usually operate very smoothly. Of course, on any twin cyl motor, onboard glow is a must. I had the saito 90 twin and it sounded really ncie when running, but had issues keeping cyl running at first. But, with onboard glow and one that is user selectable for settings(like McDaniels), you should set the on point at least at 1/2 throttle or higher. If one cyl does drop, you dont want the remaining cyl struggling to stay running at 1/4 throttle cuz you'll lose speed really fast that low.....trust me I know as I lost a graupner Extra 300 as a result. I would actually st the onb point at 3/4 throttle foe the twin 200. If one does drop, the momentum of the other one running will relight it at a decent speed(3/4). Other then that, yes the 200 will fly the plane ok. I would use a slightly higher nitro like 20 or 30% as long as the manual says its ok.
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Joined: 1/1/2006 From: Fort Collins,
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quote:
ORIGINAL: M64
kahloq, just out of interest, what are you using the gyro for?
Since you came in late to the discussion I'll repeat why
The purpose of the gyro install is to test whether it can keep the plane straight down the runway on a roll out/take off attempt. For some reason, my P-51 acts very squirly compared to Rip's and ive attempted to do anything i could to lessen that without much success. So, maybe the gyro can keep the plane straight since it should be able to react instantly to a yaw movement where my eyes wouldnt see it right away...thus I might overract and input too much rudder or not enough IN TIME whereas a gyro should only put in as much as is needed to maintain the heading the heading hold lock was set for. I am sure it will take a few test runs to get it nailed down really well before I trust it completely to keep the plane straight hands off.
Posts: 143
Joined: 3/24/2002 From: Boynton Beach,
FL, USA Status: offline
To help take off and tracking on my Frankie I have the tail wheel on a separate servo which when switched off keeps the tail wheel straight. I then mixed in some right rudder with the throttle so once the plane is on the mains it requires almost no correction for a straight take off. This can also be placed on a switch but does not really seam a problem when flying. My plane also changes attitude with full flaps and gear down needing aileron correction to fly straight. I mixed in some aileron correction with full flaps so now it it continues to fly straight with full flaps and gear down making landing easier.
Posts: 220
Joined: 2/18/2007 From: Ocilla, GA, USA Status: offline
quote:
ORIGINAL: tsyssa
I know exactly what you are talking about...I saw that weld and I might re weld mine. (Im used to doing micro TIG work...so its not really difficult.)
Dont know why they do not have more weld going around....actually I do know why...time and cost...but the small amount of time spent would make it much better.
Glad to hear someone else is having problems with the stock crap retracts. I've had two of the welds come off. Both times on take-off. The first resulted in damage to my expensive spinner. The second, resulted in a nose-over. Both because the wheel had no support to keep it in alignment when the weld broke.
Now, I've received some 704's from Springair, but they will no where near fit in there without major modification. The strut he sent was too short, and the retract itself looks much smaller than the stock. The funny thing is, I personally talked to them on the phone and explained what plane I had.
However, upon closer look, the 404's look like they might be a closer fit. Springair doesn't provide dimensions for their 700 series retracts.
Has anybody tried spring air retracts on the NEW version of this P51D?
Yes, I know there is a lengthy discussion on retracts from the OLD thread, but it doesn't really apply to the NEW version plane because the mount is totally different.
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Posts: 481
Joined: 3/12/2005 From: Fort Collins,
CO, USA Status: offline
quote:
ORIGINAL: MarvinE255
To help take off and tracking on my Frankie I have the tail wheel on a separate servo which when switched off keeps the tail wheel straight. I then mixed in some right rudder with the throttle so once the plane is on the mains it requires almost no correction for a straight take off. This can also be placed on a switch but does not really seam a problem when flying. My plane also changes attitude with full flaps and gear down needing aileron correction to fly straight. I mixed in some aileron correction with full flaps so now it it continues to fly straight with full flaps and gear down making landing easier.
Hey Doc,
Sounds like if you have to correct with aileron when you drop flaps then their deflections probably don't match up.
Ideally, you should use a separate channel on your Tx/Rx that you could attach the second flap servo to, and slave to the primary flap channel. Then, go thru the full flap range and alter the curve of the slave channel flap to precisely track the deflection of the primary flap thru it's range of motion.
I could never get Frankie's flap deflection to match until I did this, then, once done, she stopped hanging a right turn every time I dropped 'em!
All of this is, of course, is different from a pitch change due to flap deployment, which on my Frankie, needs about 3% negative elevator to compensate.
Rip
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Posts: 1698
Joined: 1/1/2006 From: Fort Collins,
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Some pics from today. 3 H9 1.50 P-51's present. Mine, Rips, and another club flyer's "Old Crow"
Mine was the first to take flight. I didnt use the gyro though. It wasnt responding properly so need to make some adjustments and didnt want to do a "field fix" sicne it would require taking the canopy off, yada yada yada....
Anyhow.....mine got up and seemed ok, but the rpm',s based off sound of the motor, didnt seem very high. It also appeared that the rpm's were slowly decreasing as the flight went on and a few occasions it felt like i was losing altitude. So, the motor will need to be looked at again and some tuning done yet again. Now.....decided I should land since the RPM's seemed to be lagging. Hit the gear switch and only ONE gear came down. Uh oh!
Tried to cycle them again. Same result. So..had one gear down and prospect for landing on one main and a tail wheel didnt really look promising. I might have actually tried it, but, those there at the field suggested retracting the one gear and belly land it in the tall grassy weeds on other side of runway. Set up for approach and dropped half flaps. Circled around to bleed speed and then dropped full flaps and let it come down to about 10 feet off the deck. Then I killed the motor and let it glide till it was about 3 feet up. Hit the elevator a little to bleed remaining speed off and it briefly stalled the left wing(with a quick recovery) plopping the plane pretty much dead on its is belly. I did hear a nasty thwack sound so I assume some damage occured.
Walked over to the plane, examined it and then picked it up and didnt seee any damage off hand. YAY! I was braced for the worst actually......and had some significant damage really occured, it probably would have soured me on the plane entirely.
So, only thing now is to figure out why the one gear failed to extend. Oh and I do have to reattached the threaded portion of the Keleo exhaust back into the cylinder head port as that came out....but...the weld on the brace of the keleo muffler did NOT break. Hows that for sturdy
The "Old Crow" is electric powered by an elfite power 160 on 12s 5000mah spinning an 18x12. Needless to say, it outperformed both Rips and mine. In fact, he has it set to limit the throttle to only 75% too. It was doing absolute vertical climbs while also doing aileron rolls straight up.
Posts: 151
Joined: 4/13/2004 From: Redlands,
CA, USA Status: offline
Hey Kahloq, I think chances are, the rpm drop you were getting was because the keleo came loose during flight and not just knocked off during the belly landing. I had a similar experience on my Frankie. When I was reading your explanation about the rpms dropping it sounded awfully familiar. turns out that it was just the exhaust nut on my keleo had come lose, so i had to re-tighten it again for the 3rd or 4th time. I have been using blue loctite, but i think i'll have to find something better this time. Also, on my tip stall accident which i had a few weeks back , i noticed the keleo was knocked completely off or detached from the head when i walked up to the plane. At first thought it had stripped the exhaust port threads completely since it was no longer attached, but believe now that it had actually come loose in preparation of the tip stall landing..... anyhow. That keleo is proving to be a problem with unscrewing in flight and gotta figure out what i can do to keep it from unscrewing in the future, i might also trim it down some to prevent it from shearing out the head if it has to hit ground hard again...... fingers crossed. Louie
< Message edited by Tisoy909 -- 6/22/2008 8:02:09 AM >
Posts: 1698
Joined: 1/1/2006 From: Fort Collins,
CO, USA Status: offline
Thats a possibility, but doesnt explain the lack of rpm's to begin with(unless it unscrewed while taking off). I dont recall it struggling so much for decent rpms on the previous(first flight) so maybe.
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RE: New Hangar 9 1.50 P-51 Build - 
