RE: New Hangar 9 1.50 P-51 Build
 

You gotta love a story where the pilot actually thinks things through before putting her in. Usually my crashes are more sudden and violent! Good luck on the fix. My 60 is still sitting in the corner while I ponder my repair. Going with a different color scheme since I've got some balsa to rebuild.

Can't seem to get the wind to stop blowing here. Temps finally in the 50's during the day, but it seems the wind speed matches the thermometer most days. Going to take the 1.5 out tomorrow and run a couple of more tanks of fuel through it and if the wind isn't blowing too much, going to shoot some taxi runs on the short strip at my house.

Went to a local hobby show this weekend, and some guy had a NIB old style 1.50 Mustang (previous edition) for 275.00. My boy saw it, and by the time I got there it was gone. Someone got the deal of the year. Did walk away with a train wreck of a TF giant Corsair for 45.00 though. Might have hope for it next winter.

Haven't heard many of you guys talking about your maidens! Who's putting them up and how are they flying? Make sure you include your power plant and mods.

RE: New Hangar 9 1.50 P-51 Build
 

Saw one of the 'old' versions fly Sunday with a Saito 180 - nice!!!! But I think I will go with a Evol 26GT after I take it out of the P-47-150.

RE: New Hangar 9 1.50 P-51 Build
 

Tom

While I no Longer own a 180 I work on them still. I find here in Florida that never ever is the low end screw flush with the Throttle arm. Typically it indented a few mm.

The best and really only way to Tune this Engine is to run her up with the proper Prop usually around 9000 rpm and lean the motor out till she peaks. Next richin her back up by 200 to 300 RPMs.

Now adjust the low end for a smooth Idle and transition to full power. Once you have done this I repeat it one more time and usually that's all u need to do with the Low end. I do retune my High end needle every day.

Hope that gets u going with her.

Ian

RE: New Hangar 9 1.50 P-51 Build
 

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.

RE: New Hangar 9 1.50 P-51 Build
 

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

RE: New Hangar 9 1.50 P-51 Build
 

It hauled butt with a 16 x 8 3 blade. Tons of power. I flew a couple of circuits at 1/3 throttle to sort out elevator and get used to a touch more aileron than was needed. I never fly dual rates. Porpoise was me taking off without full TO speed and a sensitive elevator. Sorted it out after 1 1/2 circuts. Trust me, it could have used another 3 - 4 oz up front. That would have put me just ahead of the book, maybe 3/16" or so. I know P51's. They like to slice the air, slightly nose down, ( just a hair ) not lift into it without a lot of speed. Its the downthrust thing that helps most planes. My experience is exactly the same as yours on the h9 60 except that I don't add up enevator with trim for TO. I do it with the stick. I can hold it level and, I like long "show of"f TO's, like the real deal. My old flight instructor told me you're flying the minute you start your roll. so just fly it level, son. I just nicely got airborne and a couple of boneheads simply took off as if it was an old plane. Just bad manners. I should have eased the throttle forward and trusted the engine woud take it. I was just too careful and was freaked out when the darn thing wouldn't sink when it was supposed to. I have never had a retract fail at the rails before in 10 years. And I did beef them up as usual. Its just I couldn't see the bad joints way under there. That won't happen again. I'll pull the good one and soak it too. Next, the aluminum flanges are very soft. Not at all like Robart which are very hard. Try to remember this...this plane will really slow down on its own and will float. You may not need flaps on first flights. It will land like a trainer if you don't over concern yourself. Next time I will fly it the way I fly all the others. I just got wussy.

RE: New Hangar 9 1.50 P-51 Build
 

Ran the 26 GT tonight. Showing 8100 RPM with a Xoar 18x8. Swapped out for a Zinger Pro 16x10 and read...8000. Hmmm. Figured I'd gain at least 200-250 RPM not loose 100. Granted I'm still running 30:1 for break in and haven't dialed the carb all the way in yet, but still...

Anyway, the wind was blowing hard enough to darn near unload the prop on the ground, so no taxi tonight.

Tailskid, I shot a video of the 26 GT for sound of the engine, but can't figure out how to download to post. Does sound nice though!

RE: New Hangar 9 1.50 P-51 Build
 

Bo, I think you should be absolutely sure that it was a leaky fuel tank plug that caused the engine failure - in my experience these plugs can relax after time and should be checked for tightness. However, the two cases where I experienced a leaky fuel tank plug, fuel leakage was apparent during the engine run up before flight so I never actually took off with a leaky fuel tank plug - just a thought so it might be worth a few extra minutes to make sure it was not something else.

John.

RE: New Hangar 9 1.50 P-51 Build
 

Ordered me another 26GT today...and 10 servos........hope the wife doesn't look too hard at our VISA bill!!! Guess that means I have to start working on the Mustang....darn, but someone has to :)

RE: New Hangar 9 1.50 P-51 Build
 

My 26Gt is back at Horizon. Was only tacking 7250rpm with a APC 17X10
PAT

RE: New Hangar 9 1.50 P-51 Build
 

John,

Good advice, thanks!

I didn't get into it in my previous post, but at the time, another experienced flyer and I talked about the possibility that the mixture was set too lean. This was before I tore the plane down at home and found the loose fuel tank cap. Neither he, nor I, remembered seeing the slight, but obligatory, "smoke trail" you want to see from a Saito in flight. However, we also don't remember NOT seeing it!

In the past, I've had a Saito 91 set too lean by a "club expert", and experienced a "soft seize" while airborne, which required the bearings to be replaced. In this case, I turned the engine over when I picked up the 'Stang from her belly landing, and there was no tell-tale internal resistance to rotation other than the usual compression.

It's a distinct possibility that this (mixture) is the actual culprit, so I intend to strap her down and do some careful checking of the mixture and do multiple run-ups, before she takes to the skies again.

Bo

RE: New Hangar 9 1.50 P-51 Build
 

Tailskid, what kind of RPM (and prop) were you getting with your other 26 GT? After reading BankYank's post, I'm kind of wondering if I will get that extra 6-700 RPM after break in. Just curious to see your numbers.

RE: New Hangar 9 1.50 P-51 Build
 

Mine is still 'breaking in' and haven't tached it lately., I'll do that Saturday!

RE: New Hangar 9 1.50 P-51 Build
 

I had 4, 14oz tanks of 30:1 through it (amsoil full synth). Might need more running im not sure?. The main reason i sent it in was because of the ignition. Although bought new a few months ago i believe it had the old ignition that needed 4.8v but when i called horizon about the low rpm's the tech guy said run it on a 6 cell pack or 2 lipos as the weak spark was the low rpm problem. Attached a 6 cell pack and the box started buzzing kinda loud. So rather then fry something i sent it in. If the engine is the problem or the ignition Horizon will take care of it.

RE: New Hangar 9 1.50 P-51 Build
 

I was confused about m y ignition as well, because I bought it in the middle of the GT/GT2 switch. Horizon seems to be more than willing to fix the problems though. Let me know how it turns out, in case I have problems in the future.

Even though it doesn't really belong here, I've got a question for any gas guru's viewing. I'm running Yamalube racing (pure synthetic) oil for my mix. If I switch to Klotz or Amsoil do I need to run 50:1 for another tank for new blend? And is there any chance that a different oil will give different RPM results? I'll ask on gas forum if no one knows but since I'm here...

Any one else with maiden reports? Looking to do mine soon, and looking for some characteristics to look for.

RE: New Hangar 9 1.50 P-51 Build
 

First, did everyone else building this plane only receive one "Ferocious Frankie" nose art decal? Seems strange not to have one for each side of the cowl.

Also, I wanted to double-check with you guys the "plumb-bob method" for determining CG location. Never have used this method on my smaller (60-size) planes, but it seems appropriate for this larger, heavier plane where the wing sheeting can't take the weight of the plane inverted on my "balancer" support points.

My understanding of this method is as follows:

1. hang the plane with two cords/wires from a single anchor bolt point in the ceiling; one on the nose, one on the tail (anywhere is fine) and adjust one or both of them until the plane is level nose-to-tail.

2. hang a third string with the equivalent of a plumb-bob on the end from the same anchor bolt, and it will point to the current CG point on the fuselage/wing.

3. re-locate heavy internal stuff like batteries until the plumb-bob points to the factory recommended CG point while insuring plane is still level.

Is this correct? Thanks to any who can help clarify this for me.

Bo

RE: New Hangar 9 1.50 P-51 Build
 

That is the method for finding the true CG of your model. Tie a long piece of string around your prop shaft, the other end around the fuse as close to the tail as you can ( a piece of tape helps keep it from sliding) and then hand the model from a hook. Level the model, hang a plumb bob from the hook, and where it hits is your true CG. You can also laterally balance while its hanging. I saw a link explaining this with pictures, but I can't find it now. Works really well and is a simple check. My 51 balanced within an eighth of an inch of factory recommendation.

On a separate note, Pe Rivers gave me a good link for tuning Walbro carbs and reading plugs (for you gassers).
http://www.prme.nl/forum/viewtopic.php?t=10.

RE: New Hangar 9 1.50 P-51 Build
 

Only goes on one side.

RE: New Hangar 9 1.50 P-51 Build
 

OK. That means they probably only meant to include one. Doesn't necessarily mean it's correct.

Interesting, but my 60-size P-51 had two "Marie"s shipped with the ARF.

Is there, like, a standard practice regarding REAL warbirds back in the '40's and whether they had dual or one-sided nose art?

Bo

RE: New Hangar 9 1.50 P-51 Build
 

The location of the nose art, like the content, was determined by the pilot - some had it on both sides while others just had it on one side.
John.

RE: New Hangar 9 1.50 P-51 Build
 

On the nose art, it was quite common for Mustangs to only have nose art on the left side. Cripes A Mighty is a good example of that.

RE: New Hangar 9 1.50 P-51 Build
 

Thanks for the clarification. Somehow, in spite of consuming dozens of aviation and warbird books over the years, that fact escaped me (or I just wasn't paying attention)!

Interesting that the owner of the modern day "Ferocious Frankie" has chosen to display the FF nose art on both sides of the cowl, as shown in this Duxford '06 photo. [link]http://andyvsaviationpictures.fotopic.net/p36196568.html[/link]

Anybody care to comment on my previous CG method question? Gotta do that on the big 'Stang in the next few nights...

Thanks,

Bo

RE: New Hangar 9 1.50 P-51 Build
 

Notice tail numbers. Like you, I had assumed that the nose art was on both sides. Like WWII pilots, restorers also have the right to put Nose art on anyway they want. I always go with art on both sides. BJ

RE: New Hangar 9 1.50 P-51 Build
 

OK..OK...OK

Just finished and test flew my new H 9 Mustang 1.50.

It is powered with the MVVS 1.6i (EVO 26GT). With a home built muffler, the engine is fully enclosed, save 1/2 inch of sparkplug cap. With Dave brown spinner and no bombs, I would guess the weight is around 16lb. CG came in at 6 1/8 inch which is 1/4 inch fwd of recommended.

With this engine it will not "blast off" but take off roll is about 150 ft. It will climb at about a 30 degree angle, and will loop from straight and level. Once it gets up to speed it is plenty fast enough. It will cruise around pleasantly at half throttle. The engine turns a wood 16X10 at 7000rpm.

The stall speed is slow and you get a gentle warning just before it breaks into a spin. Four points and slow rolls are smooth and easy.
I think the CG is perfect at this location as it requires little down elevator for inverted flight.
The recomended elevator travel is way too much. I cut it down to 9/16 up and down on high, and 7/16 up and down on low, then flew it on low landed on high.

Aileron travel is a little too high for me as recomended.

I love it!

Jerry

RE: New Hangar 9 1.50 P-51 Build
 

Rip N Bank: You have the cg method correct. I generally use one long string rather than two so I can slide the string over the hook to get the plane back to level after adding some weight. Here's a link with more discussion of this method.

http://www.495thsquadron.org/TechTalk-CG.htm

Brian