Rip n Bank
Posts: 502
Joined: 3/12/2005
From: Fort Collins,
CO, USA
Status: offline
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quote:
ORIGINAL: solarmusic-RCU
OK, so here's a maiden for you. I'm running a new Supertiger 2300. The plane came out about a pound light since I didn't add the bombs, left out one servo and mounted the engine way forward. So the take off...I was a little concerned about a nose over so I held a little too much back pressure on the elevator and after a nice straight take off run of about 75 feet, I was airborne, and porpoiseing a little, not having quite enough airspeed. Needed about 6 clicks of down and got things squared away, gear still down. I was a little worried about the new engine , perhaps unnecessarily so, but I sensed that it had sagged. There were other p[lanes in the air and I couldn't hear it. Brought her around for a long approach and felt really good about my position. This plane really can slow down. Did not employ flaps. She just wouldn't settle, and I was afraid to punch the throttle, so I took what I had. I caught a weel on the edge of the runway and that was enough to rip the gear out. The rear rail held. I had added a good big piece of 1/4 stock under it, but the front rail broke out and the gear flanges bent really badly like soft aluminum would. Diagnosis: make sure you are a degree or two nose heavy for maiden. Then just fly the darn thing. I was too tennative. Land very softly or go around. The gear mounts are a nice interlocking assembly of light ply, not all that well fitted and the some hot glue here and there. Not very many of the surfaces were really alligned and there was very little real glue in there. Once I rebuild the mount and leading edge I am installing Robart 660 struts (Tower $80 the pair ) I'll have to straighten the flanges and re install. Next time I'll fly with a lot more authority and make sure that I land like a butterfly with sore feet. The gear rails need as much help as you can give them even between the actual mount and the wheel well. There is a continuation of the forward rail that runs out toward the wheel that could use some 1/4 stock for support. Next time I'll fly it like a P51.
Solar,
Sorry to hear about your experience on your P-51's maiden! I did have a few questions and thoughts:
1. The SuperTiger should have enough power to fly the plane, especially if she's a "pound light." Was it at WOT for take-off? Did the engine perform nominally (and reliably) on an engine stand, at WOT with the prop used on the maiden, before mounting on the 'Stang for the maiden?
2. Porpoising could be from excessive elevator input (pilot), using high-rate instead of low-rate or expo, and/or using the full factory recommended 1/2" throws (elevator) which are believed by many in this group to be too much.
3. As for making it a "degree or two nose-heavy for maiden", you shouldn't have to. If you nailed the factory CG location when the tank is dry, then when you fill the tank, you are already significantly nose-heavy for any take-off, including the maiden.
4. I NEVER maiden in a crowded sky! Like you said, you just can't hear the engine. This is really important with a new engine! Nor do I want the distraction! I prefer "pre-existing silence," and empty skies, for my maidens, and I'm willing to wait for it!
5. I heavily fiberglass reinforced both the front and rear gear rails in the wing. If I hit something, at speed, off the runway, that takes off the gear, an appreciable portion of the wing is coming coming with it!
6. My 60-size H9 P-51 wants to go "tail-high" on my take-off rolls, and I suspect my giant-scale version will want to do the same. I've held slight up elevator in the smaller 'Stang during take-offs, just enough to keep the fuselage level when the tail wheel comes up. An alternative, AFTER maiden (RE: neutral trim is, as yet, unknown), is to bump in a number of up-trims on the elevator so you don't have to worry about managing the tail lift while you're fighting engine torque on throttle-up with right-rudder, and then trimming it down the same number of beeps/clicks to neutral when the gear is up and she's climbing out.
However, as we all know, this scenario is easy to analyze in the hangar, and hard to manage real-time on the actual maiden. I'll be doing my maiden by month's end, and will post my "results" here.
As my previous signature used to say, "Never precede any maiden flight with a statement more predictive than 'Watch this!' "
Good luck with the repairs!
Bo
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The more planes you have in your "hangar," the less likely your wife will notice a new one!
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RE: New Hangar 9 1.50 P-51 Build - 
