RE: Regal Eagle - A Journey
 

Not sure about the vibration on his DF but I know for certain vibration will strip the gears of a micro in a gasser. The nylon gear trains in them don't hold up for long with a lot of vibration.

If the vibration is that bad, are all of Gordon's servos metal gear or nylon gear?

RE: Regal Eagle - A Journey
 

*heh*

You guys appear to both be thinking along the same lines I am, actually. I'm not sure where, but I'm leaning toward the vibration idea somehow...either introducing some metal-metal contact I haven't thought about, or maybe introducing ome interference somewhere, or exposing an intermittent flaw in the servo...something.

I just don't "feel" like it's an engine problem. Lord knows, I could be wrong, but it just doesn't seem like one to me.

As for the linkages, I pla n on gettingg them taken care of this afternoon at PAC. We'd already decided on ball links, shakes. :)

As for the engine issue...eh...we'll get it solved. :) Just gotta track it down.

RE: Regal Eagle - A Journey
 

Gordon, I have been watching your build and am inpressed with your progress in such a short time. I think we met at Cane ridge a few months ago. I had a concern about you not using an inflight mixture system. This engine will not take a high rpm lean situation very well, In fact it will deffiently shorten the life on the engine and the glowplugs will not forgive you either. You realy must reconsider this option. Just my 2 cents worth. :eek:. Anyway you have a great looking F15. I took out my old JHH F86 this weekend (OS 91 DF) aned flew it a couple of times. I've been flying turbines for the past few years and It was like going back in time. Don't get me wrong here, I was a blast to hear that ol 91 singing. Good luck with your maiden. You'll have to bring it out to Neeleys Bend and fly with us sometime. Scott

RE: Regal Eagle - A Journey
 

Scott,

We did, in fact, meet...or at least I believe we did. :)

As for the in flight mixture control, I appreciate your insight...truly I do. And I really don't mind when someone with experience shares their 2 cents on this (or any other issue)...my stand is (and has, I hope, been pretty clear this whole thread) "I welcome your input and advice, as long as you accept my occaisional decision to not follow it. :)"

Much like the fuel issue earlier in this thread, there comes a time that, lacking experience as a guide, you simply MUST decide whose input and avice you're going to follow...and then go with it. If you spend all your time "reconsidering" the same advice from different people, you'll never fly. :) In this case, I have input from several people I know and trust and respect on both sides of this issue...what are you gonna do, ya know?

In this PARTICULAR case, my KNOWLEDGE (and note, I didn't say experience...and the two are vastly different, I know) led me to lean toward not using the inflight control. Obviously several folks on here warned against that decision, as well as a couple who I've met, but don't fly with on a regular basis, such as yourself.

On the other side, I found agreement with 3 experienced modlers (including 1 with significant DF experience) that I fly with on a regular basis, AND the designer of the aircraft.

Now...do I think ANY of you are steering me wrong, or hoping to see me fail? Obviously not.

I just think that this issue, like nearly everything in this hobby, can depend a great deal on how one flies, what one expects from the aircraft and motor, etc etc.

So, in the end, I wound up going with the advice of people whose advice has served me well in the pst, and who know my flying style and intent with this aircraft.

Bottom line...some times you have to choose, and if your choice is wrong...well..you'll pay the price of the lesson. :)

Sorry, I just had to go on that little tangent to basically clarify the whole issue above...I really don't mind the well intentioned advice of ANY fellow modler...experienced or not. Sometimes you're just put in a position to choose, and hopefully making a choice contrary to your advice in this case won't prevent you from offering more down the road. :)

In any event, thanks for the compliments on the build. It's certainly not a show quality aircraft, but I'm pretty proud of my efforts given that this is my first scratch build. :)

And ya know, it just dawned on me that there have been several comments about the speed of the progress...I didn't think a 6 month build was all that fast myself! :) Admittedly, however, the last month or so have gone VERY quickly, but that's a function of the kit, not me, I assure you. Once you get the pre-assembly done, the components really do go together well and quickly...credit to Bob on that, not me.

Granted, I suppose it helps when you get to wok from home most days, and thus can take a few opportunities to duck out to the shop and piddle around on it for an hour or so. ;)

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

Speaking of which, been piddling around a bit this morning...started constructing the top deck, and working out a way to make the middle portion of it completely removable..looks like that's going to go smoothly, and it is, really, the last construction left...so, we seem to still be on for Sunday, presuming of course we can get this final engine issue resolved...which, between Mike and I, I certainly expect we can.

Scott, you're certainly invited out to Cane Ridge on Sunday, around noon, to see her maiden. And, once I'm comfy with her, i'll definitely take you up on your offer. :)

RE: Regal Eagle - A Journey
 

Well, I'm now more convinced than ever that the issue was/is mechanical.

Just fired her up, and ran for 10-15 minutes with no throttle servo, moving the linkage by hand. No problems at all throughout the entire range. That being the case, I'm at least convinced the motor itself is fine, and it would seemt he fuel system is as well.

Now to figure out how to redo throttle linkage, and track down what was happening and prevent it. :)

RE: Regal Eagle - A Journey
 

Further testing confirms the above. I've run the engine through 2 complete tanks (1 "fill" ) of fuel with absolutely no engine surges or problems...all controling the throttle manually.

As a result, I'm convinced, this HAS to be problem in the old throttle control system somewhere...obviously, it could be a bad receiver, or interference, or (and this is my guess) some slop in the linkage that caused problems when vibrated.

I'm leaning toward that latter because today I noticed that the vibration in the airframe is at its worst right in the throttle range we were seeing problems in yesterday...so either it was moving the linkage, or perhaps causing some metal-metal contact (though I tested ever possible point of metal-metal contact today, and found nothing) or possibly the vibration was just beating the poor micro servo to death.

In any event, the current plan is to redo the whole throttle system with a non-metal rod, a standard sized servo, and ball links on both ends. This will require cutting into the fan shroud to get to the old linkage, but such a hole can easily be patched with fiberglass.

One bit of advice for anyone currently building, or building in the future. As designed, the fuel system WILL allow a significant amount of siphoning after the engine is shut off...resulting in fuel running out the carb into the thrust tube. Be sure to fuel proof the balsa under the engine area before mounting everything. :)

RE: Regal Eagle - A Journey
 

We can hook up my Servo X-Citer to it if you want. It does glitch detection on PPM receivers and a bunch of other servo diagnostics (current draw, sweeps, centering/deadband, etc). If its a receiver or a bad servo it will find it.

RE: Regal Eagle - A Journey
 

If the new linkage/servo doesn't solve the issue, I'll take you up on that, shakes. I THINK this is going to do it though...will let you know more later.

RE: Regal Eagle - A Journey
 

Gordon, I'm just currious how the fuel tanks are plumbed. Are they in series or parallel? and are you using pipe pressure or fan pressure? I have a bunch of df stuff laying around and would even be willing to donate to the cause to help you keep that 91 happy. I toasted my first one in a Byrons f16. It hurts to burn hole in a piston. Thats probally why OS dosen't warranty the engine. Feel free to give me a shout. I also have a heavy duty throttle arm and a tip on the throttle linkage. Scott 479-7914

RE: Regal Eagle - A Journey
 

Scott,

Enjoyed our phone conversation, even at this early hour. :) Thanks again for your time and input, and look forward to flying with you some time soon. :)

RE: Regal Eagle - A Journey
 

*blink*

18 pages of RCU thread, 436 posts...some about Shakes' stiffy, and none (yet) about "LUBE AND PROBE!!!" rjbranchii never letting me forget the fan is in backwards, and Donnie reminding me CONSTANTLY how lousy a builder I truly am compared to someone of his skill.

Tom and I finding ut JUST how sticky carpet tape is...learning to follow the MASTER plan, not the silly dimensions in the manual...discovering just how much I HATE molded plastic.

A collection of 73 prototype photos, a Franklin Mints model of the prototype, and 23 e-mails exchanged between me and current/former McDonnell Douglas engineers.

A few give and takes about fuel, in flight mixture controls, and DF engines.

6 months, an estimated 400+ hours of work, more than a few headaches, bouts with frustration, and, at last count, 73 "Oh ****!" moments.

She's done.

Assembled, Covered, Cleaned, Balanced

And ya know what? There are two emotions winning the battle against all the others right now.

1) It's really been worth it. Even if she goes into the ground Sunday, it has absolutely 100% been worth it. In Bob Parkinson I've found a new friend, who shares my passion for this aircraft, and is an absolute joy to converse with. I've learned more about building and kit bashing and covering and gluing and cutting and sanding and assembling than I ever thought possible. And I've had the indescribable joy of looking back at this whole thread, and then at the finished product.

2) Even more than 1) above...I really miss my dad. :(

Photos soon, gang. Going to head out to the field to put her through her last ground tests.

RE: Regal Eagle - A Journey
 

Standing Ovation from over here. Congrats man. Lookign forward to the 1st successful flight!

RE: Regal Eagle - A Journey
 

Yes, standing ovation. Waiting anxiously for the flight report. I have this kit also and plan on starting a build late this year. Gonna archive this thread.
Edwin

RE: Regal Eagle - A Journey
 

*heh*

Thanks, guys. Feel free to throw money up on stage. :)

Edwin, I wish you the best with your project. She's a fun bird to build, and you'll find Bob to be TERRIFIC in his support. Start a build thread yourself when you get started. Would love to follow your progress! :)

RE: Regal Eagle - A Journey
 

Here's a few quick pics out of the cheap digicam showing the finished product. Better pics will be shot this weekend with the god camera.

RE: Regal Eagle - A Journey
 

Excellent work!!

It does my heart good to see the DF contingent come out in force to support one of our brothers. If you happen to come into the Cleveland Ohio area for the Ashtabula jet meet, look me up and we can put our F-15s up together for some formation flying. Yours along with my Luke AFB TGA F-15 would look mighty fine in the air together!

Anthony

RE: Regal Eagle - A Journey
 

Now that's what I'm talking about. She sure looks good all buttoned up and ready to go on patrole. Very cool Gordon.

RE: Regal Eagle - A Journey
 

Thanks, guys. :)

AAbdu,

Won't make it up there for a jet meet, but I do, occaisionally, get up in that neck of the woods to visit relatives. Perhaps some time this year I can make a trip with the bird. :)

RE: Regal Eagle - A Journey
 

How did the latest ground tests go? Is it flying Sunday or after the races on Saturday? Looks great!!

RE: Regal Eagle - A Journey
 

Hey Shakes... is that your YAK in the photo?

RE: Regal Eagle - A Journey
 

They went well...a couple of very minor little issues cropped up:

1) The silicone bead in the pipe hanger that was preventing the pipe from rattling (and thus causing metal-metal interference) wore away. I'll be redoing it with a piece of fuel tubing, shouldn't take but a few minutes.
2) One tire is intermittently rubbing on the gear strut...just a bit of grinding on that strut will resolve that...again, nothing but a few minutes work.

Beyond that, the motor ran strong through a whole load of fuel, good throttle response. New linkage works quite well. Getting the starting procedure down pretty well now. Range checked it again, engine on, out a good 60+ feet, and that was fine. Was able to open her up a bit on the tarmac, and it seems like it takes a bit to get rolling, but once it does, it accelerates quickly (which is to be expected, I suppose) and shows no sign of bad ground handling.

Did the final balancing and such yesterday...she came out a bit tail heavy, but nothing a few oz of weight in the nose couldn't fix. I suspect had I not added the extra framing around the back plate, and the weight of the rudder servos and linkages, both back at the end of that VERY long tail moment, she'd have probably come off the board dead on.

So, I guess all that remains is to fly her. :) Plans are still to do that around noon on Sunday.

RE: Regal Eagle - A Journey
 

Well, it looks like the weather is going to force my hand...

So, I'm going to shoot for a maiden tomorrow afternoon, after the races.

RE: Regal Eagle - A Journey
 

That's a screen shot from G3 of a Yak with the QQ color scheme like mine.


Gordon, awesome - wish I had a video camera to catch the flight!

RE: Regal Eagle - A Journey
 

Well, I'm bringing one I've borrowed...why don't you be my videographer? :)

RE: Regal Eagle - A Journey
 

Gordon,

Good luck on your maiden. You may have already done it by this posting, if that is thee case I hope it went great!

You have an open invitation to join us at our local flying field whenever you are in town.
Anthony