RE: Regal Eagle - A Journey
 

Well...

The good news is she came home from the maiden in one piece.

The bad news is she didn't fly.

Decided to head out to a different airfield (Middle Point for those of you familiar with the area). Quite honestly, with the races at my home field today, there were just TOOOOOOOOOOOO many people for me to have ever gotten comfortable. So, Mike and I headed out to MP to find a quiter place.

Got everything ready to go, started the take off roll...she wanted to head left just a tad, so I gave just a bit of right rudder, and over she went onto the right wing tip...the resulting bouncing spun the nose gear about 90 degrees, which, of course, ended our flight attempt real quick.

The upside is, as I said, everything's all in one piece.

I'm NOT, however, sure why A) she headed left (hadn't exhibited that tendency in earlier ground tests) or B) Why the nose gear turned...all the gear are locked in, set screws tight, and all the wires are flatspotted where the set screws mount.

So, that being the case, rather than try a "half-a**ed field fix", I brought her home, and will go over everything with a fine toothed comb, and try again some time this week.

=============

In the mean time, learned a couple things:

First, I'll be moving the retract switch to the other side of the transmitter from the engine kill switch. I got my fingers crossed up today when she went in the grass, and raised the gear after I'd flipped the engine kill. So, probably good that I learned that lesson on the ground.

Second, she's a fair bit heavier than I'd expected, coming in at 13+ lbs, when I'd been aiming for 12. I'm not at all happy about that, and it worries me more than a little...but, honestly, not a whole lot I can do about it now.

Ah well...all part of the hobby, i guess.

RE: Regal Eagle - A Journey
 

gordon
your r.e. looks beautiful!! im glad to hear that your taking your time with the maiden flight. youll get there. as for your weight, its fine if you were 16+ pounds there would be some concern, at 13+ your fine, the lightest byron jet that i have is 12+ and they fly great. my last mig 15 weighed just under 17 pounds and it was a handful(notice i said was)i had every bell and whistle i could put on it trying to make it a scale bird. bad decision on my part to say the least. i have learned the k.i.s.s. method the hard way. (keep it simple stupid) you are a good builder, if anyone can scratch build something as beautiful as your jet well, my hat is off to you my friend. good luck on your maiden... donnie

RE: Regal Eagle - A Journey
 

I was wondering where you went. I looked around after the races, it really cleared out pretty quick. Where is middle point? Is that the Murfreesboro site at BFI?
I don't blame you for going somewhere a little quiter. I will be maidening a new bird next week and will do it away from my home field as well. Just don't want that many eyes on me.
Good luck with it. It looks great.
Randy

RE: Regal Eagle - A Journey
 

Thanks for the insight, donnie, and the compliments. :) I'm just understandably paranoid. :)

Randy,

Yeah...I kinda felt bad about it, actualy, because there were several people out there I would like to have around, and I know they're anxious to see her fly. But, honestly, it was, as you said, just TOO many eyes. My biggest concerns was that I'd here "When are you going to go??" one too many times, and snap someone's head off...which would, of course, not have been in ANYONE's best interest. As it was, we DID have a minor fueling issue initially (don't panic Tom, it wasn't the old one! *heh*), and man,...if I'd been surrounded by 9,487 people offering "help", I'd have gone balistic. *heh*

I'm going to resolve our gear issue this morning, and then kinda hang out, and see what the weather's doing...I doubt it'll give me a shot, wind-wise, but hey...we'll see.

RE: Regal Eagle - A Journey
 

Gboulton

This is kelling me! Somehow my subscription to this thread got nuked back about page 15! I missed everything since! I thought you must have just gotten things delayed some and not posted. Plane is looking real nice! I wouldn't worry about the weight. Heck, at that weight I would think in the least you would install active ejection seats that launch if the pcm looses signal! Was good to see the video. I was worried with that motor facing the wrong way it might go backwards.

I have really leaned from your pre maiden testing. I would not have gone into all that until I saw how much you found from all of it. We don't have any pavement to taxi on. Maybe I'll take it over to a chruch parking lot to taxi around. Only pavement here on the Island I live on. The grass strips at my club fields are basically fields to get airborne from as fast as you can. I was suprised at how much vibration you describe. Any thoughts the source? The fan impellor, or possibly the mounting of the fan? In seeing posts from others with other DF's commenting that its normal makes me think its the cantilever mounting of the engine mounts in the fan units. Wonder if a more solid mounting of the fan motor mount to a supporting structure would help decrease it? Any thoughts?

Good luck on the maiden flight. Send videos... not of the plane, of your knees during the flight.

bob branch

RE: Regal Eagle - A Journey
 

Nahh...we were just discussing lube and probe issues, and figured you wouldn't want to hear about that, so we had your subscription removed. ;)

And, obviously, I didn't mention...the plane DOES go backwards...at least at first. I installed the new Dynamax VPDF (Variable Pitch Ducted Fan)...you must have missed that post when your subscription got nuked. ;)

Yeah, I have to admit, I'm very VERY glad I've done it. The notable thing is, obviously, even all that ground work STILL didn't find all the problems, as noted above (and below)...it's definitely an airplane that, ime at least, you very much want to get all the bugs worked out on the ground that you can.
Ya know, honestly, I don't think it's a lot of vibration, in the scope of things. I mean, sending a single piston up and down at roughly 4 bazillion RPM...well..it's gonna shake a bit. :)

But, in terms of vibration as though something's out of "balance" or whatever...no, I don't see any of that.

So, I think the "oh my gosh, the vibration!" reaction...I think that's just a knee jerk thing when you see what that little motor running THAT fast can do. :)
LOL. You're a hoot, Bob. :)

The content of my video will be up to the videographer...you will, I hope, excuse me if I busy myself flying the plane rather than directing. ;)

===========================

As for the maiden...well, another aborted attempt today. SEVERAL bugs cropped up, which I'll share here:

1) The pipe hanger gave us some problems...after the silicone I'd originally used to isolate the pipe in the center of the hole gave way, I'd redone the hole lined with fuel tubing...well, THAT idea failed (I'd left the edges of the hole too sharp), so, of course, w epicked up a BUNCH of RF off the metal-metal noise. Resolved that one by saying "Bah" to the pipe hanger. Seems to be plenty stable enough back there, with the spring mount up by the engine head, though obviously I don't want to leave it that way for long. I suspect I'll just make up a pipe hanger from plywood and be done with it.

2) Then we had some engine issues...engine didn't want to needle well, or transition happily, and was running hotter than I liked...all signs, of course, of being too lean, but given where the needle was (in relation to full closed) I couldn't IMMAGINE it was...so, some troubleshooting (thanks, mike!) of course identified a bad glow plug...replaced that, and had a MUCH happier engine. Lesson here: Plan on replacing the glow plug frequently, and ALWAYS be SURE you have a good plug in. The existing plug heated just fine on a driver, and had no broken wires...but closer examination showed the wires toward the bottom to be stretched out, and the coil rather loose...in any normal engine, i doubt you'd even have noticed a difference.

3) Ok...finally...we have a correctly needled, smooth running, POWERFUL motor, no radio interference, and good flying conditions. LET'S GO FLY!....vroooooooooOOOOOOOOOOOOOM! ZING...down the runway...ok..looking good...hey...umm...where are you going? left? LEFT?? No no,...right please...no...I said RIGHT. AHEM! RIGHT!

The plane ignores all suggestions to head right, and coasts (I had, thankfully, reduced power) into the soft grass at the left edge.

Hrmm...

Back to the stand...oh...it appears one of the mains has turned a bit on its strut...that's odd, but not completely unrealistic...so, we check everything, tighten everything down, check all the gear...ok...happiness. Let's go try again.

Start engine...good. Check controls. Good. Everything's happy. Mike sets the plane on the ground...off we go taxiing to the end of the runway....

"Stop! I see the problem!" yells Mike.

"^(*^(& &*(&*(& **(*(*#^& !^%&^@^& #^&*@^#&*" yell I. "Ok...i'm coming back, Mike."

"Look at your left main."

"Hrmm...that's not right...it's leaning IN, not out."

More cursing

A thorough check reveals that the retract mount appears to have broken loose from the bottom of the fuse. My GUESS is that, in the early days of having the retracts in, that gear would bump the fuel tank when retracted. I have since fixed that issue, but I think, during the first several cycles of the gear after installation, it probably weakened that epoxy joint, and it decided today was the day to fail.

It's good, I suppose, that it did so NOW, rather than later...but ARGH.

I want to FLY. :(

Oh well...all part of the game, I guess...back to the shop we go where repairs will be made, and then to await another day of good weather.

RE: Regal Eagle - A Journey
 

Gboulton

And I thought I was having tech issues returning to control line aerobatics! Man, I'm glad tearing up half my house and adding a second floor has intereupted my RE build project til the house and you get done so I know what to expect! You should syndicate this on network TV, the ratings would be astronomical. People could bid on if it goes up or just heads for the tulies again.

The tuned pipe connector system recommended to me by the RC pattern fliers is a silicone coupler. I got mine from http://www.rcaerobats.net/products_page.htm. I also got a real nice pipe mount with a rubber bushing about half an inch thick that mounts with a bolt. I think Bob Pastorello at rcaerbats recommended it to me but now I cannot remember its source, but he was very helpful when I was setting up my first pipe plane a year ago. The pipe is held to this mount with a very heavy ) ring about 11/2 in diameter. No vibration rf and none at the pipe motor end.

btw, how did you create the finish on your afterburner exhasts. Very nice effect.

bob branch

RE: Regal Eagle - A Journey
 

Gboulton

I found the source on that pipe hanger. Its a "hush clamp" from DB products.

bob branch

RE: Regal Eagle - A Journey
 

Bob,

Thanks for the info on the pipe hanger. I'll check it out.

As for the tailcones, stupidly simple really. :) Shot them with a coat of UltraCote Primer Grey, and then mixed up some plain ole' Testor's high gloss black with a bit of thinner...airbrushed that on using a very light pattern, just holding it in one place longer when I wanted some buildup...basically, I just shot in the "grooves" between the "blades" cut into the tailcones, and then fanned it out towards the tips.

RE: Regal Eagle - A Journey
 

Gboulton:

If you are running the right fuel, with the engine on the rich side the glow plug should last at least ten flights (I use Wildcat 5% and McCoy Nº 9 plug). A have an Avonds F15 with a ramtec and OS91 and at the 12th flight I decided to change the plug just in case but the engine was running perfect.

My first ducted fan was a Regal Eagle with a Byron setup. Great Flying bird.

I don't recommend flying without a pipe hanger, even if it seems stable, the vibration is high and without the pipe hanger the O rings that seal the header to the pipe won´t last long.

Regards
Eduardo

RE: Regal Eagle - A Journey
 

Gboulton

About that testors black not being fuel proof and tail slides.... well if you are taxiing backwards you will run into the same problem... glad to see you have canards in that direction though.

bob branch

RE: Regal Eagle - A Journey
 

Eduardo,

As I said above..I don't plan on running without a pipe hanger as a permanent solution by any means...it just got us going for the day.

As for the plug, I hadn't expected it to last very many flights at all...thinking back on it, that one's been through over 1.5 gallons of fuel, break-in and all that, so it was certainly time for it to be replaced.

RE: Regal Eagle - A Journey
 

Hi Gordon,
Thought I would jump in.
The vibration you talk about seems a lot more than normal.
If any thing you might get vibration at low rpms.
The high rpm vibration is a buzz. if you put your hand on the fuse it should be a buzz. this is hard on glo plugs and radios but it should not shake anything loose.
There is a difference between your jet shaking from vibration and buzzing.
Your impeller could be out of ballance.
Have you checked rpm with a meter?
If your impeller is out of ballance you will not get 21000 rpm.
Also, if it is, this would account for the lack of controll on the ground.
I have seen a jet with an out of ballance impeller dance across the runway.
This can happen if you are not on the pipe. there is a lot of vibration until you needle it in and get on the pipe.
This does not happen on grass.
Hope this helps,
Bob Parkinson

RE: Regal Eagle - A Journey
 

Hey Bob,

I'm not sure why everyone's suddenly jumping on this vibration thing. :) I really don't think there's that much....it's just a loud engine that rattles things because it's movi9ng at 4 bazillion RPM. :) I mean, a lawn trimmer or chain saw "vibrates" too, in the sense I'm talking about here. It's not ANYTHING that seems "out of balance", or is shaking badly, or anything like that.

The only time _I_ mentioned vibration at all was that I thought that might be the source of the original throttle problem...and, in a sense, it was...I had a weak servo and poorly done throttle linkage. Since then, the only "vibration" issue has been the pipe contacting the metal pipe hanger...given that we're talking about a clearance of 1/16" there, I don't think that's really "excessive vibration" in the pipe. *heh* And, again, that wasn't due to the plane vibrating, it was my poor quality work on isolating the pipe from the edges of the pipe hanger.

The plane doesn't "dance", or "shake violently" or anything of the sort. There's absolutely NOTHING about the plane running that seems at ALL out of line with what I'd expect from a plane turning that many RPM's in a motor fixed to the fuse with hard points. It comes up on the pipe fine, and at full throttle sits quite calmly in a flimsy PVC rack, doing nothing but being VERY loud and obnoxious. :)

Relax, gang. You jumped on a phrase or two that was, I think, taken out of context. :)

RE: Regal Eagle - A Journey
 

IF your wife doesn't ask if she can sit on it while it's running, it's not shaking that bad! LOL

RE: Regal Eagle - A Journey
 

Today is the day.

I can just feel it.

We're going to fly this afternoon.

RE: Regal Eagle - A Journey
 

Well..... Did the eagle soar?

RE: Regal Eagle - A Journey
 

The stress is killing me. Did it, did it?
Edwin

RE: Regal Eagle - A Journey
 

I agree man... I'm purple from holding my breath.

RE: Regal Eagle - A Journey
 

I have the feeling he's out flying maiden right now. It's a gawjus morning here, while it got pretty windy yesterday afternoon.

RE: Regal Eagle - A Journey
 

*heh*

The answer to your questions lies below....it just took me a while to decide exactly how I wanted to write this up. ;)

================================================== =========

Ok...I won't make you wait. Yes. It flew.

It didn't do it for very LONG, mind you, but hey...when the Wright Brothers flew that far it was hailed as a stunning achievment and a great leap forward for mankind.

Don't worry...it's not damaged badly, just a dorked nose gear...not a tough fix at all.

Now for the story...allow me, please, to advise anyone building this aircraft (rjbranchii, you payin attention??? :)) that the story contains some VERY important setup information. You'll know we're at the important part when loud bells start going off, and a big lobster comes out and pinches your nose for effect.

So...we get to the field. It was a PERFECT flying day...what little wind there was was right down the center of the runway, and blowing in my favorite direction. The Eagle fueled up nicely, all the preflight checks went well...it looked like we were a go.

So, out to the end of the runway we head...one last check of the control surfaces, and we're off! Full throttle, accelerating nicely...plane tracks right down the center line, needing only VERY light steering corrections. She's running straight and true, and really coming up to speed. About 200' or so down the runway, it is universally agreed by everyone that we've got plenty of speed to fly...except for the airplane. The conversation went something like this:

Me: "Ok...we should be good...up elevator...."
Airplane : "VROOOOOOOOOOOOOOOOM!"
Mike : "Up elevator..."
Me: "Hrmm..not flying..more elevator..."
Airplane : "VROOOOOOOOOOOOOOM!"
Mike : "UP ELEVATOR."
Me : "Hrmm...ok..MAX elevator."
Airplane : "VROOOOOOOOOOOOOOM!"
Mike : "UP ELEVATOR!!!!"
Me : "It's HAD up elevator for a while, mike! It ain't flyin!"
Airplane : "What's that green stuff I'm about to run into??? Oh, and VROOOOOOOOOOOOOOM!"
Me : "Crap!" *chop throttle - kill engine*
Airplane : "Wheeeeeeeee! The grass is so cool and soft."
Mike : "That's odd."
Me : "Grumble mutter grumble"

So we head out to retrieve the aircraft, not quite sure what's going on here. No damage to the bird, so that's good at least...but it sure doesn't seem like it wants to fly. So we think, and discuss, and look, and examine. Finally, we "experts" all come to the following agreement...BP's reccomended 1/2" of elevator travel simply isn't enough to lift the nose. So, we crank the elevator travel up as far as she'll go (about an inch), and decide to go fly again....or at least decide to go tearing down the runway at Mach 4.3 again...the flying part will be up to the airplane.

Please note...the absence of horns and/or lobsters IS A CLUE.

Once again...full throttle, down the runway we go...again, the conversation goes something like this:

Me: "Ok...we should be good...up elevator...."
Airplane : "VROOOOOOOOOOOOOOOOM!"
Mike : "Up elevator..."
Me: "Hrmm..not flying..more elevator..."
Airplane : "VROOOOOOOOOOOOOOM!"
Mike : "UP ELEVATOR."
Me : "Hrmm...ok..MAX elevator."
Airplane : "VROOOOOOOOOOOOOOM!"
Mike : "UP ELEVATOR!!!!"
Me : "It's HAD up elevator for a while, mike! It ain't flyin!"
Airplane : "What's that green stuff I'm about to run into??? Oh, and VROOOOOOOOOOOOOOM!"
Me : "Crap!" *chop throttle*
Airplane : "Wheeeeeeeee! LET'S FLY!!!!"

There are, at this point, three VERY IMPORTANT things to note:

1) I've chopped the throttle to idle.
2) The airplane is flying.
3) Those first two things happened in that order.

Ok...I'm going to throw some highly technical terms at you here. We have a jet airplane flying with NO POWER. This is, in strict aerodynamic terms what we "experts" call BAD.

Immediately, my fingers run home to momma, and do what they ALWAYS do in this situation. ADD POWER! Nearly as quickly, the brain catches up to the fingers and says "No, morons, power is useless here. The plane is 5' off the ground, you don't have time moron." and commands the fingers to chop the throttle again.

At this point, we get to the first truly good news of the day...the plane, she settles right down and truly does fly dang near like a trainer. No tip stalling, no rolling, no pitch problems...NOTHING unexpected. She just glides like she's on rails, responsive to all control inputs just as you'd expect. So, off the elevator quickly, let the nose come down a bit, and she glides right on down to the ground, stable as a rock.

She'd likely have been fine, save having reached some of the rougher ground...a small "crease" in the ground (too small to call a ditch really) looms ahead, and the nose plows into the dirt, busting out the nose retract. That was, however, the only damage.

"Ok, fine" I hear you saying, "but what about the horns and lobster???"

Patience..we're getting to that part.

So, we bring her back. The AAR goes something like this:

1) Ok, one thing we DO know...it's going to fly just fine. It was, without a doubt, THE most stable aircraft I own in a power off configuration. So, clearly, we've nailed the CG and lateral balance, as we thought.

2) We know the plane's a bit heavy at 13.7 pounds...but it still oughta fly sooner than it did. I mean, there are 14-15 lb RE's out there that fly fine. However, since I have to get into the nose ANYWAY, I'll likely see if I can squeeze the battery in between the nose retract and top of the nose, which will move it a good 3-4" forward, and let me shed some of the 10 oz of nose weight I added...that'll help a BIT, but probably isn't the reason we're using the whole runway to fly.

3) Ok, i really don't expect this thing to get off the ground in the 80 or so feet BP claims...it's kinda heavy...but hey, I've got 400' of runway...so I'm FINE if it takes 150-200 feet, ya know? This whole 395' takeoff roll thing though...that's an issue. the airplane's TRYING to tell me something, and I don't know what yet.

Then it hits us....or rather, it hits Mike.

CUE THE HORNS AND LOBSTER!!!

The wings need to be at a positive incidence angle with the aircraft on the ground.

BP says, in the pkans, the wings should have a 2 degree positive incidence angle with the plane on the ground. He goes on to say that, if one does not have an incidence meter, one should set the nose gear at 4.5" from the bottom of the fuse, and the mains 4" from the bottom of the fuse. Not having an incidence meter, I used the latter method.

CUE THE HORNS AND LOBSTER AGAIN!!!

When we had the issues with the gear early on, I did much futzing with them...and, when they went back together (here's where I man up and own up to my own stupid mistake) I simply DID NOT CONSIDER THAT BIT OF SETUP THAT IMPORTANT, and TLAR'd the gear.

What I wound up with was an airplane that sat, probably, just about dead on level on the ground.

Note, please, fellow F-15 fans, the the entire fuselage of this aircraft is one big flying surface...in fact, it's estimated that it's roughly 40% of the flying surface. BP's model is no different. the fuse is, in fact, vaguely airfoil shaped. Now, BP very carefully designed certain aspects of this aircraft...one of them being that in straight and LEVEL flight, the application of power should NOT balloon the aircraft...it should STAY LEVEL.

Ok...so here we are on the ground...LEVEL (or perhaps even slightly nose down) and we apply power. Go figure...AS DESIGNED, the increase of airspeed did NOT balloon the aircraft...it STAYED LEVEL.

"BUT!" i hear you say..."You were applying up elevator!!"

Yep...that's pretty much what I was thinking too....but let's look at the aircraft from the side, shall we??? The stabs are slightly below the wing, right?? With the aircraft LEVEL, where is the elevator when in the up position? Nearly RIGHT BEHIND THE WING....in other words, not seeing a whole bunch of air.

Now, all things being equal, they see ENOUGH air do do their jobs with authority...but that's if everything's equal.

On the ground, it's not.

Again, think about the shape of the aircraft...specifically, the inlets. Where do they point? Straight ahead? NO. SLIGHTLY DOWN. Think also about the rear of the aircraft...if it is, in fact, sitting even just a BIT nose down on the ground, the thrust line is PUSHING THE NOSE DOWN.

Boys and girls, I just built the worlds fastest skateboard...WITH, in a manner of speaking, DOWNFORCE. :) All this on an aircraft that's NOT getting as much air under its lifting surfaces as expected.

Go figure...pull the power off, the "downforce" goes away, the elevators, despite not seeing as much air as they should, are now seeing ENOUGH, and do their job..nose comes up, FINALLY the wings and fuse see the proper AOA, and since we have PLENTY of speed...she flies.

So...we'll repair the nose gear, CAREFULLY reset all 3 gear to provide the appropriate postive angle of incidence for the wings, and try again. :)

===========================

For what it's worth, I've owned or currently own 9 aircraft not counting the Eagle.

Of the 9, I did some sort of minor damage to 7 of them early in their careers...frequently on the first flight (or aborted flight). I ADORE(D) each of those 7 aircraft, and had a blast with all of them...still have several, and enjoy them immensely.

The other 2 never got dinged early....one gave me no end of engine troubles before it finally died, the other is a "What will it do THIS time?" non-trim-keeping nightmare to fly.

It bodes well that the Eagle saw minor damage on her first flight. :) Quite honestly, strange as it sounds, NOTHING could have made me more comfortable the next time we go to the field.

RE: Regal Eagle - A Journey
 

It looked great with no power on, no tip stall, no rocking - just straight and true. Get the incidence taken care of and it'll go like a bat out of hell off the runway :)

So, video? :D Or was I shaking too much :)

RE: Regal Eagle - A Journey
 

Gboulton

RE: Regal Eagle - A Journey
 

Shakes,

I'm not going to sare the video since...well...frankly, I just don't feel like sharing such a miserable performance. :) The video LOOKED fine, actually...of course, I really didn't give you any TIME to shake. ;)

Bob,

Yes? :)

RE: Regal Eagle - A Journey
 

Well thats at least reasonably good news. I know exactly what you mean, I did the same thing on a wing mfg P-38. Set it up level on the table and it wouldnt rotate. Sounds like next time you'll have it licked.
Edwin