RE: NEW H9 P51 Mustang 60 ARF
 

thanks for the feed back guys. Now I am really challenged on the engine choices. I like the 2-stroke because I think they are very reliable and low maintenance. Also I would want to keep the weight down because based on this forum it seems that weight is the biggest challenge.

dionysusbacchus - I am happy to hear that someone has success flying the blue nose!

RE: NEW H9 P51 Mustang 60 ARF
 

For what they are being sold for, even if I have to learn more re these motors, I just cannot bring myself to look past those DLE20 gasers, as with the Jtec wraparound pitts with the 1.25" can, the only bit sticking out is the spark plug and exhaust stacks - someone sent me some pics of that combo in the bluenose, and it looks SWEEEEEET!!!!!!.
All that and they are lighter than the Saito FG20's this thing is spec'ed on.

RE: NEW H9 P51 Mustang 60 ARF
 

After six flights with the CG moved forward to 4.5" I can confirm that this is a good CG to fly at. In an inverted 45 deg climb, I needed slight push on the elevator to maintain the climb. This is just right for a stable CG. It also did not nose over, and stalls were very tame with flaps up. With full flaps, I could almost NOT stall it, and a little wing rock is all it would do with nose up, power off.

So the CG at 4.5" is highly recommended. Now this warbird flies great!

RE: NEW H9 P51 Mustang 60 ARF
 

Watch how nice this bird takes off, slow and fast passes, and lands!! I did not have the sound system on, otherwise you could hear a Merlin engine and guns. Maybe next time.

http://www.youtube.com/watch?v=zI76rAbhQI0

RE: NEW H9 P51 Mustang 60 ARF
 

Hi,

if somebody has pictures of Blue nose with DLE-20 in cowl,please make an upload on this forum.
I would like to see how does it look like and how much cowl must be cut.

Thanx

Danijel

RE: NEW H9 P51 Mustang 60 ARF
 

This is not my specific Blue Nose (get it next month for my b/day), but this is a pic of the H9 P51 blue nose with the DLE20 (using an aftermarket wrap around pits muffler) - comes up really nice IMO - hope mine does thats for sure!

RE: NEW H9 P51 Mustang 60 ARF
 

Any body puttin' one of these devil planes together? It was a good thread , sure is quiet now. Well I've still got one in one piece, and will maiden this spring. Did most of the mods my own special way except for moving the tank down and back. And my fix for the tailwheel is second to none, in my opinion, all internal and easy too. Still thinkin' about.moving the tank . Tuning the elevator sounds like a good idea also. I think i'll reduce elevator throw and add a little rudder. And for sure set c.g. at 4.5".

RE: NEW H9 P51 Mustang 60 ARF
 

I just got one a couple weeks ago that was on backorder. It looks improved over pics I've seen of older models. The LG mounts have been beefed up. Now the ply ribs supporting the gear rails run the full width of the chord. The center rib is 1/4" thick, and the shear webs are glued in securely. The balsa skin seems a little on the crumbly side, though, based on how it cut while modifying the gear bays.
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Some of the pin hinges supplied with the kit looked sketchy at best - the pins didn't look all that secure, and compared toRobarts, they are pretty weak. SoIchanged them out with Robarts. Theinstructions still call for "Hinge Glue" which was only madeby Pacer (Zap), and has been discontinued. I've come up with agreat substitute: Mix Pacer or equivalent white canopy clue 50/50 with Titebond or equivalent aliphatic resin.
</div><div>I'm modifying mine for semi scale gear and doors. The kit's main LG is positioned about 1" outboard of the scale location, which is apparent by retracted wheel location, but it doesn't detract from the overall appearance (the inner doors will be a little spread apart). I'm using Robart 7/16 offset struts, which are a perfect fit for the 3.5" wheels. I already had a set of Robart diamond treads from a "retired" model, so I'm using them. Looks like H9 didn't do anything to improve the disintegrating wheel problem - in my opinion, this is a combination of the plastic resin they use and the design of the hub. If you compare to a Robart, you will immediately see the difference. No ding on H9 though - they are still nice looking wheels, and the best I've seen in an ARF. </div><div></div><div>I like the H9 retract units - the integral servo mount makes for a stiffer, more reliable linkage. I modified the Robart struts to fit, by cutting them to length and adding a machined upper fitting to the strut. To get the gear to retract fully with the offset struts, you have to adjust the angle of the retract unit by carving the gear rails and/or adding spacers (I did both). It was only then I realized the retract units are 85 degrees! I was able to modify the retract unit for 90 degree operation, but it took some serious work - it requires moving the pivot point of the link arm by about 0.050". To do this, I milled out a pocket centered on the new location, and added a machined bushing.</div><div></div><div>It looks like H9 didn't do anything to upgrade the tailwheel assembly. The main problem is that it's basically half a mount - you need two - not one - bearing to keep the thing from wobbling around. Also, there's not much structure in there to support it. For me though, it really needs to be retractable! I plan to put the Robart .60 size retractable tail wheel in there, but I'm still thinking about how to go about it. I'm considering making a complete module (gear unit and doors, with formers) that will essentially plug into the bottom of the airplane. That way I can fabricate everything off-ship, then install it as a unit once everything is working.</div><div></div><div>I've already found out the hard way how delicate that flat clear coat is... Ironex will attack the covering, but can be used sparingly. You've been warned.</div><div></div><div>My stabs were dinged and there were some minor dings in the wings. H9 needs to do something about their packaging. On mine, the stab dings were on one side, and since the stab is symmetric, I just chose that as the bottom and ironed them out as best as I could.[img][/img]</div><div></div><div>For power I'll be going with the RCV-90SP (I know some of you have been anticipating this...), with a 4-blade Zinger 16x10 prop. Looks like the motor and muffler will fit completely inside the cowl (although that pre cut hole is still there).</div><div></div><div>I'll post more pics separately with descriptions

-Tom-</div>

RE: NEW H9 P51 Mustang 60 ARF
 

Here's the modified Robostrut. I cut both the upper and lower unit to get the length needed. The adapter is machined stainless, silver soldered to the strut. I adjusted the unsprung height by grinding off the stop under the scissors to 5/32, then adding a wheel collar. I removed the stock springs and used fuel tubing inside for softer action.

RE: NEW H9 P51 Mustang 60 ARF
 

Here's how I modified the retract units. There are two moving parts, which I call the trunnion (which the strut attaches to) and the link (which the servo drives). The relationship between the trunnion and link pivots determines the rotation angle of the retract. I moved the link pivot down (towards the mounting flanges) 0.055" and towards the trunnion pivot 0.004". This increases the extended angle to about 89 degrees, but keeps the retracted angle the same. This required that I grind off quite a bit of metal so the link and trunnion would clear each other during operation. To move the pivots, I milled a hole centered on the new pivot location, but large enough to completely eliminate the original hole (about 0.25"). Then I milled a pocket about 5/16 diameter and 0.020" deep so that the stepped bushing would lock into place. The stepped bushings are custom made from brass round stock, and press fit into the side plates with 0.002 interference fit. I made a jig with the hole positions first, before taking the chance of ruining my side plates. The two pics show the trunnion in the retracted and extended position. As mentioned in other posts, I had to cut part of the side plate away to clear the scissors.

RE: NEW H9 P51 Mustang 60 ARF
 

Here's how I mounted the retract servo - I used a Hobbico unit, and had the same problem everyone else did. I came up with a nice way to mount the servo with a little pinch bracket. I used LHS (that's local hardware store!) angle aluminum, then bent it into a step. The screws go through two holes in the bracket, but sit beside the servo instead of going through its mounting holes. Also, I put 0.030" spacers under the servo to keep the gear leg from hitting the servo housing. Note - the LHS aluminum is too hard to bend as-is. It must be annealed or it will crack. It's important not to get it too hot - the way I do it is to put a mark on the part with a Sharpie, then hold it up to the torch until the ink disappears and let it cool. This will anneal it enough to bend but not too much.I've included a before and after shot of the gear extension angle, and pics of the gear retracted and the gouging required to get the correct retracted angle.

RE: NEW H9 P51 Mustang 60 ARF
 

FireScout, I love that inner gear door. How will it be actuated? It would be great to see pics of that as you go.

RE: NEW H9 P51 Mustang 60 ARF
 

Firescout, very nice work! Are or were you a machinist? Thanks for all the info! Again, nice modifications to the original kit. First class mods!!!


Mike :D

RE: NEW H9 P51 Mustang 60 ARF
 

Thanks for the comments!

tclaridge, The inner doors will likely be actuated by micro servos, with links in approximately the scale location, which happens to be convenient. I'll be sure to post more pics.

Mike, I'm not a machinist by trade - actually an engineer, but I've made a chip or two.

Tom
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RE: NEW H9 P51 Mustang 60 ARF
 

I like the inner door mod. I installed different servos in my retracts also, lucky for me we have full time alloy welders (staff) on site, so I had one of them weld 4mm wide x 2mm thick 'plates' into the servo opening, closing all bar one of the supplied servo screw holes with a quick weld also. The is it was just a case of re-drilling new holes and bolting the servos in place. Ended up with nicely mounted servos that work the retracts an utter treat now (bluebird digital metal gear retract servos used ex Hobby King for like $13 each).

I'm curious, did your plane have that wooden 'hook' on the underside of one wing to secure the radiator scoop? .... as it's not even listed in the instructions, and nothing I have seen elsewhere mentions it, just wondering if it's a new addition?.

RE: NEW H9 P51 Mustang 60 ARF
 

Bob,

Mine has the hook. I noticed the same thing. Oddly, those ridiculous drywall screws are still included in the kit!

I'm considering coming in from the top with the wing bolts as others have, but not sure. I may want to glue the hatch on, since mine will be glow, and I probably won't need access from the top. I haven't heard any reports as to how well the hook and magnets work.

Welding in an extension is probably the way to go. I had to grind some clearance into my gear mounts as the bracket I had made was bumping into them - but I don't have a welder (nor can I do TIG).

I didn't mention earlier, with this mod, I moved the servos to the opposite side. I cut some clearance in the wheel well liner, and trimmed the skinny rib right next to it to allow the retract unit to slide in without the need for the little access panel. I modified the access panel to fit the outer gear doors, then glued it in place.

RE: NEW H9 P51 Mustang 60 ARF
 

I used hook and magnets on the radiator scoop with no issues. It has not fallen off, and makes it easy to add. Wings bolts on first, then just push on the scoop. Scoop stays with the wing for storage as I glued my wing together.

RE: NEW H9 P51 Mustang 60 ARF
 

Thanks for the heads up on your finding and how yours worked out (you too Firescout), perhaps that hook is a plain to see key to weather or not yours is a newer one (re factory mods over original item released a few years back).
Still ..... back to my build.

RE: NEW H9 P51 Mustang 60 ARF
 

Question for those of you with non-modded main wings, with everything installed on your wings (servos, gear etc), what did they come in at re all up weight? ...... I know I'm using metal geared digital on EVERYTHING, but at about 1.7kg (3.74lb) for my main wing, I'm wondering if that's too heavy for the 'specked' AUW of 4.5kg for this thing?

I'm starting to think that the DLE20 I'm going to put in this baby will be the right idea!!

RE: NEW H9 P51 Mustang 60 ARF
 

My wing weighs 4.27 lb. That is flying weight that includes the radiator scoop, but not the two wing bolts.

RE: NEW H9 P51 Mustang 60 ARF
 

Thanks, I should be around that with scoop aileron/flap control links added.

RE: NEW H9 P51 Mustang 60 ARF
 

Hey guys I did a quick search but didn't find anything regarding my issue.  The paint on my cowl flakes off just looking at it... half of the paint is gone already.  Anyone have the same problem?  Or could it be the paint on my cowl? 

RE: NEW H9 P51 Mustang 60 ARF
 

I've read both this thread and the one on RCG, and don't recall anyone compaining about the paint flaking. My cowl is really thin, and cracked around one of the screw holes, so I'll need to reinforce it with another layer of glass, but the paint seems fine. Your problem sounds like something HH will cover under warranty.

Tom

RE: NEW H9 P51 Mustang 60 ARF
 

Firescout, very nice work!  It's great to see this thread come back to life a little.  I will say this about your build though, watch the weight. It seems that the really detailed bluenoses (heavy) were having issues. And I think the weight on the directions are a joke 9.25 to 10 lbs? Good luck with that .  Also a correct c.g. is  crucial, i.e. 4.5". Just my 2 cents.

RE: NEW H9 P51 Mustang 60 ARF
 

hemi,

Thanks for the great advice and kind words. From my experience a plane with this much wing area should fly just fine at 12-14 lbs, but it will fly scale. Still, I estimate my build to come in under 12 - we'll see... From what I've seen studying everyone's videos, a combination of tail-heaviness, too much throw (per instructions), flying technique (too much elevator too soon), and wing loading adds up to a plane that will bite you if you don't respect it. I have a VQ Hurricane .60 that is about 12.5 lbs that files great as long as you keep the speed up - get a little too slow and it will snap. Almost every ARF I've ever had comes in tail heavy and over the specified weight. Maybe the weight on the box is really the shipping weighthttp://www.rcuniverse.com/forum/js/f...sn/biggrin.gif

I would bet that the CG mentioned in the instructions (4.75 - 5) is correct for about a 10% static margin (the 25% MAC point on the wing is at 4.875 if you measure from the LE at the root), but as long as you don't overdo it, a little nose weight never hurts. I think I'll heed yours and others' advice, and at least start out at 4.5". I believe what makes the Mustang touchy, and has a lot to do with it's overall flying qualities and "feel" is the stabilizer and elevator effectiveness. The Mustang's stabilizer is situated above the wing - enough so that the effect of the change in downwash with angle of attack is less than on other airplanes. This causes the airplane to seem twitchy because of higher than normal elevator effectiveness. Also, this kit has a scale elevator, which is about 30% of the stabilizer chord - that makes the problem worse. I know a lot of guys that fly warbirds like negative exponential on the elevator - I use -30% on my Hawker. To me, adding negative expo "feels" just like moving the CG forward, and you get the benefit of better ground handling.http://www.rcuniverse.com/forum/js/f...wink_smile.gif

I have my inner doors rigged up. The trick with this is getting the right amount of throw. My seqencer doesn't allow you to adjust the endpoints, so I estimated where to put the door horn based on my servo throw with a long arm. I started with the arm straight up for closed - for a door locking effect, but had to clock the servo arm towards the door and shorten the link to get enough door movement. On my setup, I'm using the standard futaba cross horn with three legs cut off, and the outer hole. Door horn pivot is 9/16" from the door hinge line. Since the servo mount is glued to the wing skin, I had to stiffen the skin underneath by gluing a piece of 1/8" lite ply (grain runs along the span, so that the ply can follow the curvature) underneath. It has the added benefit of reinforcing the servo wire hole, which would normally get torn up by the eventual tugging at the servo wires during handling.

Here's a video of the gear in operation:

http://youtu.be/OU3_H2CDAds

Added the outer doors - doors are linked to the struts with Robart gear door brackets.

http://youtu.be/bzjm9ThuhJ0

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