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VQ P-61 CONTRUCTION

Old 08-22-2005, 09:58 PM
  #351  
MANFRED
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Default RE: VQ P-61 CONTRUCTION

Good God Sam, there's no one flying that plane!!
Old 08-22-2005, 10:14 PM
  #352  
William Robison
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Default RE: VQ P-61 CONTRUCTION

Manfred:

Sam's plane has the very latest in AFCE systems - RNAV combined with auto-land, and the very newest part, auto-take-off. No doubt he has CAS in there too.

Haw.

Bill.
Old 08-23-2005, 02:46 PM
  #353  
samparfitt
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Default RE: VQ P-61 CONTRUCTION

This was one of the first UAV's (top secret back then!).
ps: sometimes the way I fly, it appears so!
Old 08-24-2005, 05:40 PM
  #354  
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Default RE: VQ P-61 CONTRUCTION

Scary P-61 Story:

Last Saturday, I suffered a left engine-out on my Ziroli P-61. Not the engine's (G-62's) fault.. a fuel delivery problem.

I had a little bit of altitude (100'), good airspeed, and 5 seconds of warning (gurgling).

By using constant, heavy counter-rudder (about 1/2 full throw), and higher throttle, I was able to stabilize the plane, make two 180 turns into the good engine, and land uneventfully. Once I found the optimum rudder setting, I flew primarily with ailerons and elevator. The only scary moment was on final approach as I brought throttle down, I thought I might back out of rudder a little...WRONG!

Overall, it was quite stable on one engine. Much better than my beloved little P-38 monsters. In fact, it flew a lot like the P-38 with engine-out on the G-2 simulator, which I always considered too easy to be realistic.

I hope this doesn't happen to anyone else, but I know it will, and I hope sharing the experience might help you prep mentally. And, yeah, I'm braggin'.

mt
Old 08-24-2005, 10:57 PM
  #355  
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Default RE: VQ P-61 CONTRUCTION

mt,

That's not too scary a story- it sounds like you had full control all the way down. And only 1/2 rudder needed with enough power applied to fly the plane around. I hope that the VQ responds as well!
_______________________

I am still feverishly working on my 'Widow- applied the stars and bars and invasion stripes to the booms this evening. I drew up all the nose art myself a few weeks ago and e-mailed the files to Stan at Cutting Edge Graphics. He promises to have everything to me early next week.

I am taking a 3 days off this weekend and I have 4 days off for the holiday weekend so I should be able to get everything tied up very soon. I think I have all the tricky parts to the assembly worked out and if there are no new surprises the plane may even be ready to maiden by the end of the holiday weekend.

I was hoping to get the plane to Pensacola, but now it looks like I'll be travelling to Europe that Sunday morning (work is getting in the way again!) But maybe I can make it to Warbirds over Carolina at Triple-Tree on the 17th...

Walt
Old 08-24-2005, 11:07 PM
  #356  
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Default RE: VQ P-61 CONTRUCTION

Walt,
Nemesis4u here... Post some pics of the Widow... I am looking forward to seeing it on its wheels.. Talked with Lenny at shindin...told him I need him to "fix" my nose wheel strut for me like he fixed yours up...
Old 08-25-2005, 07:07 PM
  #357  
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Default RE: VQ P-61 CONTRUCTION

I'm already pulling the plane all back apart. We have a tropical storm heading our way from Florida (should be here around Sun PM) and the prevailing wind has shifted, reducing the humidity to "comfortable" for the first time in many weeks. I'm going to finish detailing and painting all the trim parts while conditions are right.

Having Lenny take care of the nose strut is an easy way to go. Not only can he shorten the fork, but he will take care of cutting the strut down and fitting a metal bushing for the steering arm shaft, tapping set screw holes etc. I remember making some minor adjustments to get full travel on the spring damper when I got it back. I think that I cut the inner tube down a little and maybe shortened the spring a bit. But getting the strut right without a good machine shop would have been tough.

Does Lenny still have the CAD drawing I did for him with all the critical dimensions? I'll give him a call and see... I haven't visited or called him for a while anyway.
Old 08-25-2005, 08:56 PM
  #358  
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Default RE: VQ P-61 CONTRUCTION

Thanks ..let me know if he does and tell him to hurry on the OV-10 Gear..that we all are waiting as patiently as possible...
If he has the dimensions for the Black WIdow let me know so I can send him my gear for my Widow..
Thanks
Old 08-28-2005, 10:17 PM
  #359  
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Default RE: VQ P-61 CONTRUCTION

I didn't get to talk to Lenny this weekend, but did meet a friend at the field today who was at his shop earlier, and he mentioned that Lenny was talking about working on P-61 struts... I'll try to remember to give him a call tomorrow.

Tony has my spinners primed and ready for paint, Stan is ready to print/cut my nose art decals, I got all of my trim painting done this weekend (well almost), and my P-61 is scattered from one end of my basement shop to the other with various "operations" underway.

... no, a 36" long 2-56 rod is not quite long enough for the elevator linkage, but I saw some 40" rods at a LHS Saturday... I need to add spacer blocks to raise the elevator servos up a bit... Bill is ready with all his supplies for custom servo wiring (need to set up a date for the "wiring party" some time this week)...

I am going at it full-bore now. Still have tomorrow off and a 4-day weekend coming up. The wife is being patient 'cause even she can see that the plane is getting close to being finished

Walt
Old 09-04-2005, 01:03 AM
  #360  
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Default RE: VQ P-61 CONTRUCTION

I have my P-61 all assembled again. Before I pull it back apart once more (maybe for the last time?) here are some pics.

I've got both booms 100% complete now. Engines, tanks, servos, linkage, gear, doors, trim...

I still have some odds and ends to tidy up on the wing assembly and on the main pod, and I also have to complete the wiring. The main reason for assembling the plane this time was to find the balance point before locating the batteries. Even with the YS engines the plane is tail heavy, so the batteries will need to go up front in the nose.

I am getting very good at assembling/disassembling all the pieces- I've done it many dozens of times now... The last pic shows the PVC frame I built to hold and transport the plane. It also comes in handy during assembly/disassembly.

Tony did an outstanding paint job on the spinners!!! Pictures don't do the gloss black finish justice. I'm still waiting for the nose art and other odd decals to arrive. I am very happy with the invasion stripes and I am hoping that the stripes, red wing tips and red trim on the cowls will not only dress the plane up but also help make it a little easier to see... I should find out pretty soon.

Now that everything is about finished I'll take some detail pics of the "inside" of all the parts to show you guys how everything is set up.

Walt
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Old 09-04-2005, 05:44 PM
  #361  
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Default RE: VQ P-61 CONTRUCTION

Walt.... Looks Great...I mean AWESOME!!!!!!! Do show Lots more pics so we can see how you installed the electronics...radio...batteries etc... I also want to see your landing gear doors operate/mounting etc...
Old 09-15-2005, 05:41 PM
  #362  
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Default RE: VQ P-61 CONTRUCTION

Well into final assembly now!

What a mess, I hope that I don't have to pull everything apart again any time soon. Wires going everywhere!

I was going to take some detail pics of the inside setups when everything was ready to go. But then we got motivated to assemble the plane and try it all out, and I didn't pull out the camera until assembly was well along. But I'll take pics up into the gear wells, etc. once the mess is cleaned up.

Actually, taking the plane apart shouldn't be too bad once all the final setup is complete. But I still hope I don't have to do it any time soon.

The receiver and all the controls will be located under the top cover. I built a false floor that the gunner now sits on- this allowed me to cut an access way from the fuse to the area above the wing. The batteries are mounted in the nose area since the plane balanced very tail-heavy even with the YS engines. It will be a lot easier to move a battery back under the top cover if I need to than it would be to move one forward!

I can't wait to button everything down, clean it all up again, and glue in the pilot, crew and canopies! The target for maiden is a week from this Sunday, right after our club's Fall IMAC contest. We'll see how things progress over the next week.

Walt
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Old 09-23-2005, 05:53 PM
  #363  
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Default RE: VQ P-61 CONTRUCTION

Walt,

Are you still on schedule for the maiden flight on Sunday?
Old 09-23-2005, 10:22 PM
  #364  
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Default RE: VQ P-61 CONTRUCTION

There's about a 50:50 shot of getting my 'Widow airborne on Sunday.

The plane is finished and I am playing with the radio programming and rates this evening. I managed to drop-test it a few minutes ago (retracted the gear by accident). No damage- it was going to happen eventually anyway.

I am going to fire off the engines in the morning. Both have about a gallon through them and they ran flawlessly on my Extra. But they haven't been run for a couple of months now and never on this plane so who knows. If the engines run good tomorrow then I am probably still on for Sunday.

I'm going to let a "very experienced" buddy (Bill) maiden it for me- this plane may be at the limits of my flying abilities, and if there are big problems on the maiden then I want to give it as much of a chance of survival as possible. But my knees are already knocking anyway!

Word of the impending maiden has already spread through the visiting IMAC'ers and club members. There should be quite a crowd.

Walt
Old 09-23-2005, 10:40 PM
  #365  
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Default RE: VQ P-61 CONTRUCTION

While I am at it here are a few pics showing some setup details. I am more of a builder than a flyer (I can out-engineer myself in a hurry!) but I really like the way most of my ideas on this plane worked out. So here are a few to consider...

I set up the flap linkage in a conventional manner to get good positive control of them, instead of going through the wing with the supplied linkage. I also got rid of the bellcrank on the center flaps and just added another servo. I had to expand the hatch openings a bit for the center flaps and then make new covers to mount the servos but this was pretty simple. One of the benefits of the ARC was that this sort of creativity was pretty easy without having to worry about the covering. The servos are tied together with a matchbox.

I am activating the gear doors using micro servos that are connected to the doors with custom-made ply horns. I used a JR channel expander to drive both the air valve and the three doors. The gear switch signal is programmed to go from one endpoint to the other in 2 seconds. First the air valve is tripped and the gear go up, then the gear door servos are tripped and the doors close. Toggling the switch reverses the sequence to open the doors and lower the gear. Using the channel expander also allowed me to set the endpoints for each of the gear door servos independently so that they close fully and are set even when they are opened. This works great and is very cool.

The gear doors are attached with regular CA hinges. The full-scale plane used "piano-wire" style hinges so this setup actually looks correct. There is a slight curvature to the main doors that I took care of by sanding a slight relief on the edge of the doors before covering them, so that the CA hinges would fit and work right. This could be a problem with using CA hinges on an ARF.

I used hard piano wire to connect the steering arm links to the servo. The ends at the servo hinge by using a combination of a pull-pull connector and metal clevis combination. The clevises swing outward when the gear is raised, hinging at one end at the servo arm and at the other at the piano wire/pull pull connection. This is very repeatable- I've cycled the gear many hundreds of times now and never a hint of a problem. We'll see how it works at the field.

Walt
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Old 09-24-2005, 11:23 AM
  #366  
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Default RE: VQ P-61 CONTRUCTION

Waaay Cool Walt.... Please show more pics ...how about of the main gear doors/nacelles...and of the P-61 from side and above!! Great job!
Old 09-24-2005, 11:40 AM
  #367  
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Default RE: VQ P-61 CONTRUCTION

I brought the P-61 outside for the first time and fired up the engines this morning. The good news is that both of the YS 110's are running strong! No vibration issues, good idle, transition, top end, etc. The bad news is that I discovered that I broke the tip off one of the 4-blade props when the plane dropped off of the gear last night. And then the other slipped during an engine run this morning and ran into the spinner, scoring the prop up pretty good and bending the spinner a little. Arrrrgghhh!!! I know that you have to tighten the xxxx out of the nuts, and I haven't had one slip for a long time...

So I sent the wife to the LHS to pick up a second 2-blade spinner for the pair of APC 15x8's that I have. Actually, I was thinking of running these props for the maiden anyway just to make sure that there is no lack of power. At 9800 RPM and approx 15 lbs thrust each with the two-blades I am quite sure power will not be an issue!

Last pics before I take the plane to the field tomorrow...

The red/yellow background on the nose graphic was supposed to be red/orange so that the white lettering would show up. I'll get Stan to cut me another decal.

The wiring is neat now! You can see how I ran the wires to the main pods through the front bulkhead and under the panel that the gunner sits on.

We'll see how it flies tomorrow!

Walt
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Old 09-25-2005, 12:55 AM
  #368  
scale dail
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Default RE: VQ P-61 CONTRUCTION

Darn it looks like those 110's stick out of the cowel. I was thinking of using those too. I wonder if the YS .63's would be enough power? very nice bird!
Old 09-25-2005, 07:01 AM
  #369  
samparfitt
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Default RE: VQ P-61 CONTRUCTION

The OS FX .91's are about the only engines with enough power to not protrude out of the cowls.
You may be able to only have a hole just for the plug but I put a large enough hole in to insure the engines remained cool.
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Old 09-25-2005, 02:05 PM
  #370  
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Default RE: VQ P-61 CONTRUCTION

build-n-flyer-rcu:

That's a really nice build job you've done. Congratulations!

Can't wait to hear about the maiden.

Sorry you're not flying the maiden yourself. You're the only one who deserves the thrill of such an event. I'm sure you'll find it to be a friendly and gentle flier.


mt
Old 09-25-2005, 06:25 PM
  #371  
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Default RE: VQ P-61 CONTRUCTION

Well we didn't get to maiden my P-61 today. The airplane was ready but the weather wasn't- it was very gusty and after watching the IMAC guys really struggle with landings we decided it wasn't worth taking the chance on the maiden flight of a high-$$ airplane.

But I did get to show it off to everyone which was very satisfying after the months of work. We synch'd the engines, and before packing everything up (it had calmed down a bit by then) we ran the plane up and down the runway a few times- and actually got it just off the ground once or twice for a short distance.

The new plan is to try to fly it this Wednesday afternoon after work.

The un-muffled YS 110 engines are going to be awesome on the P-61!!! With the two-blade props we found they have enough power to get it off the ground from our grass runway using less than 1/2 throttle. And the sound is incredible... its easy to imagine the two big radials thumping... the airplane looks and sounds just plain mean!

Everyone agreed that the 4-blade props will probably be a lot more appropriate, and may actually make the plane easier to fly. With the two-blade props the torque is just incredible and you really have to baby the throttle to hold the plane straight down the runway. So I'm going to order a replacement four-blade prop tonight.

Kram, I know I am supposed to have the "pleasure" of maidening my own airplanes. I generally do, and I also have no problem maidening other folks' trainers and 40-60 size sport planes. But I've only been flying R/C for a few years now, and the closest airplane I've flown and landed to compare with this bird is my 150 size H9 P-51. Or maybe the Twin-Air?

Pic- I have the easy job while synching the engines, I have two beginners hard at work holding the plane back.

Walt
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Old 09-25-2005, 10:47 PM
  #372  
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Default RE: VQ P-61 CONTRUCTION

Actually, I didn't call it a "pleasure." I called it a "thrill." Somewhat like a cardiac stress test .

It looks darn good, even with the silver spinners.

Don't baby the throttles too much. Like any over-powered tri-gear twin, your Widow's heart and soul are the engines, and once you get those babies goin', all that rudder/aileron/elevator stuff won't mean as much. Power will pull you off the ground.

My Ziroli-61 is way over-powered with G-62's, but on takeoff roll, once I'm sure the engines are spooling up about the same, I go to full throttle. My philosophy is I can correct for a lot of imperfections easier than for insufficient power.

Besides, it's a rush!

I can tell you appreciate all this last-minute, unsolicited advice, so I'll offer one more tiny bit: be careful about what kind of shades you wear, especially if it's not a perfect sunny day. At a distance, this black plane will silhouette in an instant, making it hard to tell if you need to give R or L to level the wings.


mt
Old 09-27-2005, 12:34 AM
  #373  
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Default RE: VQ P-61 CONTRUCTION

Walt-

This might sound a little crazy at first but I can assure you that it works very well.

Nearly all of my "twin" experience has been with a grossly overpowered Tigercat that my buddy built for warbird racing. It was rather small (67 inches or so) with a pair of heavily modified YS 1.20 4-strokes running upwards of 75% nitro. It radared at 160 mph in level flight.

There was no such thing as throttle transition with these engines; they loaded up, coughed, sputtered, then finally cleared out and ran like gangbusters, but never transitioned together. We would start one engine, bring it up to temperature, adjust to peak, back off a bit, then shut it down and do the same thing with the other engine. Check plugs, top off fuel, then carry to the line for a heat. During our start/launch window he would start each engine at idle then he and a helper would carry the beast out to the runway for launch. While they were carrying it out I would gradually advance the throttles, timing it so that the engines had cleared out by the time they had set the plane down on the runway. One guy would hold the tail and I'd go to max war setting and wait until the engines came into sync. More often than not they did, I'd nod, and he'd let go. It was off in short order and there wasn't really time to correct or even mess anything up. Count to "one" and rotate!

For a sport set up, needle/adjust as you prefer, have someone hold it on the runway while you run it up, then let it go after they're both at full power. It may seem scary at first, but it's way better than trying to keep it going straight down the runway as each engine transitions at a different rate. It'll be over before you know it. If an engine sags after release (very unlikely for a YS) simply chop the throttle and ride it out on the ground. When things go poorly in 2 dimensions they seldom get any better by adding the 3rd.

Airspeed over the surfaces (and quickly) is your best bet.

After you're comfortable with the airplane and the engines then a scale-like take-off (gradually advancing the throttle) will be easily accomplished. I wouldn't even think of it for a maiden, though.

Good luck!

Tony[img][/img][img][/img]
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Old 09-27-2005, 04:41 AM
  #374  
Build-n-flyer-RCU
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Default RE: VQ P-61 CONTRUCTION

Wow, what a beautiful Tigercat!

Luckily I am not experiencing near the difficulty that you are describing, otherwise my knees really would be knocking!!!

Both of my engines are running smooth- no sputtering or hesitation. But from the experience running it up and down the runway, its important that the throttle be very gradually advanced. Until you build up some speed, if you "goose it" even just a little the stronger engine can try to throw the plane off track before the other engine catches up. I get this same effect on my Twin-Air with the tuned mufflers so its not a new experience, but it seems that the P-61 with the two-blade props is going to take "overpowered twin" to a new level for me. I hope the airframe is good and strong on this bird!

For some reason one of my engines is running incredibly strong even for a YS. Its turning the APC 15x8 just shy of 10,000 RPM and throttle response is near instantaneous. The other is a few hundred RPM weaker all the way through the range and just a tad slower to spool up. Its probably nothing that you would even notice on a single-engine plane, but with the two running side by side the differences are very obvious!

I compensated by dialing down the strong engine using the throttle curve which seemed to work fine. But I plan to tinker with the setup on the weaker engine to see if I can find the "sweet spot". It was interesting that the strong engine is throwing a lot more smoke when spooling up- opposite of what I would expect. I'll start by verifying that I'm getting full throttle, then tighten the valves a bit and maybe richen up the regulator. Just part of the fun!

Wednesday afternoon is still looking good! Of course I could just wait for my replacement 4-blade prop to arrive... naaahhh.

Walt
Old 09-28-2005, 08:30 PM
  #375  
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Default RE: VQ P-61 CONTRUCTION

My P-61 flies!!!

My buddy Bill took the plane up twice today, the first flight to trim it out, and the second to do a little "stress testing".

Here is a link to video of the second flight- it includes not only the takeoff and landing, but also a high speed pass, "F-14" style vert runs, a loop and a roll. Thanks to my wife Teresa for not only putting up with me during the build, but also for taking the video!!

[link=http://flytrca.org/video1.html]P-61 Video Page[/link]

The two YS 110's are a whole bunch of engine for this plane. Takeoff was at less than 1/2 throttle. The only time that Bill opened it up all the way was the one pass and vertical runs. I still don't have the 4-blade props but I think they are going to work well, probably still a bit insane.

Both flights were absolutely flawless. Some down trim on the elevator and a couple clicks on the ailerons was all the trim that was needed. The plane tracked great, the gear operated flawlessly, the flaps were predictable at 30%, take-offs and landings were uneventful, and the YS engines ran great.

I'm going to take a shot at the sticks Saturday morning.

Thanks to everyone here for the support and advice, especially SamP for starting and doing a great job on the build thread. The info was a tremendous help!

Walt

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