radfordc

My Feedback: (14)

Wie gehts, Hardy. Wilcommen hier.

I had the pleasure of living in Germany for 4 years. Such a beautiful country.

You will love the "Jug".

Todd D

My Feedback: (51)

Hardy,

congratulations on the maiden flight and subsequent. You will love that plane, it will soon become your go to plane to take to the field. I've had mine for several years and hundreds of flights. I still love it, nice flyer and easy to land.

Congrats again.

Todd d

kurrikan

Thanks you Lifer and Ac2.Today i started to build the dasboard.I use balsa,evergreen plastic.o ringsand a little patience.and by now this is the result .Tomorrow i will be paint it black and i will add some decals.Slowly the tornado comes to life!!!

Hardy_H

Hello again,

thanks for the warm welcome and @Todd thanks for the congratulations... although... that's not my plane in the video, that was just an interesting sounding Jug I found on YouTube. My plane, if I can even call it that, is just a few bundles of wood in a cardbord box.

Anyway, today at work I was bouncing around some thoughts about landing gears in my head. I emphasize that I have, at this point, zero experience with retracts so these idea might be completely silly, or they might be so obvious that it's the way it's often done. I literally have no idea what I'm talking about. So, three things:

1. Hybrid landing gear
2. Slowing down pneumatics
3. Twisting your wheels

1. Hybrid landing gear.

Obviously I need to gather more knowledge before I can make an informed decision on what landing gear to use in my Jug. For now I think I might prefer a pneumatic one. But the thought occurred to me that it might have some advantages to use both kinds. In a hybrid landing gear so to speak.

I think it should be possible to attach the air tank to the wing. Either on top of the wing, or, which would be the really elegant solution, in the belly pan. With the tank in the drawing it could be a very tight fit, but I guess one can find other suitable tanks, a slightly slimmer but longer tank of the same volume would make this easier. Attach the servo and control valve to the wing, too and use the pneumatics only for the main landing gear. You would have eliminated the need to connect/disconnect any air tubes, reduced the amount of tubing and the number of connections, and thereby reduced the number of possible failure points. And you could still operate your landing gear for maintenance or cleaning purposes, even when your wing is not connected to your fuse, by simply manually turning the servo arm.

Then use an electric tail gear feeding of the receiver batteries. That shouldn't put too much of a strain on your electrical systems, especially if you're using a dual battery system anyway, which I intend to do. So, using both kinds of landing gear, pneumatic and electric, might actually simplify your equipment and increase the reliability of your pneumatic mains? Just how reliable are electric tail gears? Also, if the tail wheel doesn't come out it doesn't have to end in a tragedy.

2. Slowing down pneumatics.

You know an RC airplane has a pneumatic landing gear when you see the gear slamming up and down at lightning speed. Does it have to be that way? First, it doesn't look pretty. Second, doesn't it put some considerable mechanical stresses on all kinds of parts that cannot be beneficial to the longevity of the gear?

Ok, this is either really silly or really obvious. If I insert some metal stoppers into my air tubes, with only a small hole drilled through them, it would slow down the airflow in the tubes and make the landing gear come up and down at a more civilized speed. It shouldn't affect the functionality of the gear as eventually the same amount of air will get into the pneumatic cylinders as without the stoppers. It just takes a little longer. I guess.

3. Twisting your wheels

Looking at this thread I gather it's difficult but possible to build your landing gear so that it completely fits behind closed doors. I guess the main problem is the "leading edge" of the wheel in the wheel well? It occurs to me that you could could move that leading edge slightly up or down by twisting your gear legs so that the wheels don't point exactly straight forward. If you have to twist them so that they point inwards, it might even be beneficial. Also, a friend at our club recently maidened a smaller Thunderbolt he'd bought second hand. One of the wheels pointed so definitly outwards that it hurt my eyes. I implored him to correct that before flying the thing. He didn't but still didn't seem to have any problems handling the bird on the ground.

Let me explain. At our club we use to bend our landing gears so that the wheels point slightly inwards. It's supposed to stabilize the course during take-off and landing. I'm not sure if it really has a measurable effect. You probably have to believe in it. The idea is that if your plane start skidding, the wheel speeding ahead will create more drag than the wheel lagging behind. That is supposed to bring your bird, self correctingly, back on course. This little illustration should explain it, the angles are, of course, exagerated.



As I said, just some unqualified and possibly really silly thoughts on landing gears. If you now feel the need to ask who the hell let me out of the loony bin, don't hold back.

Nighty night.
Hardy

Lifer

My Feedback: (1)

Interesting ideas! I have always preferred the reliability brought about by simplicity. Any component you bury inside the structure will be the first one needing maintenance. We call that "Murphy's Law." I prefer pneumatic gear and if that is your choice, Robart already sells airline restrictors that impede the airflow and slow down the gear cycle.As far as orienting the wheels inward, that's called toe-in and it works very well in most cases.
You will enjoy your P-47. It is a well designed plane that leads one towards success.

radfordc

My Feedback: (14)

Hardy, you're "hybrid" gear is exactly what I have. I put the air tank for the main gear in the belly and the air control valve in the wing so that the only connection to the fuselage is the air valve servo. My tailwheel is a Hobbyking electric unit. This all works very well.

To slow down the main gear, slip a wheel collar over the air line and use the collar set screw to clamp the line enough to slow the action.

FireBee

My Feedback: (34)

Another TarHeel Hal bites the dust.

well being up late last 2 nights, I of course posted in the wrong P-47 thread. Here is link:

http://www.rcuniverse.com/forum/rc-w...elcome-62.html

oh and it's a new paint job as everyone has he same ARF. Dupli-color auto touch up spray paint from auto zone. Chrysler silver. Over the monokote.

some pics:



E

kurrikan

Hi,i finished all the pieces of the cockpit of my jug!!!!!!!tomorrow will mount definitively into the plane!!

kurrikan

Great sheme on your plane!! congrats!

SWORDSN

My Feedback: (13)

The needles on the Robart valve also let you control the retract speed.

Hardy_H

How did you modify your belly pan? Could you post a picure?

I was thinking of building the belly pan so that the tank could later be inserted, and if necessary extracted again, from one of the ends. I'd like to avoid a big access hatch, but I totally agree with Lifer that equipment buried in the construction might, to stay within the image, haunt you from the grave. This slip-in belly pan might require an air tank with a smaller diameter than the big Robart one. The Robart has about 700cc and without looking to hard I already found slimmer 500cc tanks. Considering the lack of a pneumatic tailwheel I guess that would suffice. And if not, how difficult can it possibly be to build your own custom air tank?

Also, searching for a pic of your belly tank construction you might have already posted (found none), I looked up your profile and saw that you also have a Great Planes P6-E. I had one of those,too, which was unfortunately short-lived and fell out of the sky on only it's second flying weekend. RC was completely dead. It was ugly. I liked the plane a lot, so I stashed away a second ARF kit before they went out of production. I also happen to have a DLE30 lying around, same as you have in your P6. I was thinking of putting the two together but I'm a little worried the plane might be too over-powered with that and fly very un-scale like. (First one had a OS FS 120, but I'm kinda done with glow engines.) What's your experience, are plane and engine a good match?

radfordc

My Feedback: (14)

I used a smaller Robart tank and just built it into the belly pan before sheeting. I made a small hatch that allows for access to the air lines that attach to the tank. You can see the hatch in this pic. The fill valve and a pressure gauge are mounted to the hatch.

radfordc

My Feedback: (14)

A DLE 30 is a great match for the P-6E. I don't consider the plane overpowered at all. I fly mostly at half throttle and have extra power when needed. Did you see this video?

https://youtu.be/QWUW-jFBTKY

<iframe width="560" height="315" src="https://www.youtube.com/embed/QWUW-jFBTKY" frameborder="0" allowfullscreen></iframe>

kurrikan

Hi radford,i have a question about your air tank,How do you fill these bigs air tanks? do you use a manual pump or maybe some type of electric system?

radfordc

My Feedback: (14)

Here's the low down on my setup. The air pump is a cheap Harbor Freight pump with a LiPo battery for power. I used a hand pump for a while....too much effort. You can see the air tank hiding inside the belly pan. With 125psi of air it's enough for at least 5 cycles.

kurrikan

Hi radford,thanks a lot for help me,i have a little 12v compressor like yours but the main proble for me is how to adapt the conect of the compresor to the robart air valve.

radfordc

My Feedback: (14)

I used a replacement valve stem to connect to the compressor. I then glued a spare Robart fill valve into the valve stem to connect to the airplane. ¿Comprendes?

haefeli

Cut the air pump hose and insert a plastic reducer and then use Robart hose and valve. I forget where I got mine years ago but I think an auto parts that had a rack of odds and ends. It is white plastic and I think used for windshield washer type stuff.

kurrikan

comprendo

haefeli

I have looked into other air valves, my plane needs both needles wide open to get the retracts to work fairly well. I'd love to have them sequence slower but what the issue is that causes issue is volume. System on my plane doesn't work well under 70 psi. If Robart made 1/8 inch line air system then we could slow things down and assure locking of mechanism. I don't use foam tires and plastic rims. So I do have some weight, my system opens the tail wheel then mains separately due to volume. I run the big tank in the fuselage.

Hardy_H

As I'm only in the research and development phase of my Thunderbolt project it's time for some reading. There's many books about the Jug out there and I obviously can't judge how the ones I got compare to all the others. Anyway, I got these two for starters and thought I might share my first impressions:

- Robert Peczkowski: Republic P-47B-D Razorback
- Cory Graff: Thunderbolt At War


Peczkowski's RAZORBACK should be a very, very useful resource if you want to beef up your build with scale details. Loads of detail photos, drawings from technical manuals, 3-views including every rivet line and so forth. I suspect that a few of the usual suspects in this thread have this one in their shelves, too. Or Peczkowski's other book about the Bubbletop versions. Which I guess is just the same, only with bubbles. There's a number of color profiles, which are, as the name suggests, side-view only, albeit with some description of upper and under surfaces. These might suffice for a paint job although, depending on your scale enthusiam, you may want to track down additional information. What text there is, is very dry, mostly just rattling of technical data, version or serial numbers. Not so in the next book:

Graff's THUNDERBOLT AT WAR really invites you to read it cover to cover. I'm three chapters in, so far it's very interesting, and from some looking ahead it seems to stay that way. The chapters each cover different aspects of the Jug's history and in it's entirety the book seems to deliver a well rounded knowledge package. It starts with a bio of the company founder and the designs preceding the Jug. Then a chapter about the P-47 construction. Right now I'm reading about the wartime production in the aircraft factories. I guess you don't get that in very many books. The following chapters will be about the different roles of the Thunderbolt in and after the war. You know, first as a bomber escort, later as a fighter bomber. One probably could go more into detail with each of these aspects, but IMHO the amount of information is just right for the writing not to drift off into the realm of boring. Of course there's also loads of interesting and pretty pictures. These are clearly not selected for their usefulness to the RC airplane builder but they illustrate the books narrative very well.

So all in all I think I didn't choose too badly from the many books available. Both seem well worth their price, one as a building reference, the other for some extended background knowledge.

While we're talking about backround knowledge, there's loads of... everything... on YouTube these days. Most of you have probably seen these already, but this seems a good opportunity to link these two videos which I found quite interesting. One is an instructional film for Jug pilots in training (of which there is also a three-part version around with some additional introductions. I guess you could call the other one a "motivational documentary" about Thunderbolts as fighter-bombers in Italy, seemingly produced in '44 but only released after the war. Though this one made me stop when they were talking about randomly attacking houses in the vague hope of hitting German troops. War sucks.

https://www.youtube.com/watch?v=9KnwIYwEh6o https://www.youtube.com/watch?v=PJ3edFWBTMs This concludes today's lesson.

Lifer

My Feedback: (1)

I use the Robart restrictors on my gear. If the pressure is below 80psi, they won't lock in the up position. I usually end up at 120 psi. Oddly, the P-40 Robart gear does fine at 80 psi. Could be the airflow is pushing them up.

Hardy_H

@radfordc: Thanks for the information on your airtank solution, I might do it in a similar way. Seems unlikely that the tank itself should ever be damaged, so as long as you can get at the tubes it should be ok. As for the P-6E, it seems to have lots of power in reserve. I guess I'll just have to hold back on the throttle when I build my second one. A project that I somehow keep pushing back in my prodution queue.

haefeli

Scribe walk around on P-47. Alot of perfect pictures of detail. I will attempt to forward link from my work computer. Cell phone don't cut it.

haefeli

I know we are so far apart. Too bad Tony and the rest of us could be together one day with our anes and have lunch and BS till we are blue in the face. I enjoy the build as much as flying. My plane came in heavy as I knew at 30 pounds. Glass, primer and aluminum plus the moving features I knew it was going to be heavy. I still would do.it again even if it only just flies. It is beautiful to just look at and my wife thinks I'm nuts. After 4 years I feel like a traitor as I ordered 2 DLE55RA engines and gear and everything from Ziroli for a P-38. My credit card is smoking and that was 3 days ago. I'd like to rotate props outboard but I don't know where I can get scale counter rotate carbon 3 blade scale prop. I wrote Pierre at Modelbau in Germany but the lucky sob is on vacation till middle may. Where I feel my plane took a hit balancing is I have the rudder servo and all switches , air stuff in the tail so nothing shows. My RDS system is flawless with no slop but added tail weight. I did alot of work to my DLE 55RA engine (yes I like these alot) and it'll come in at 36 all up weight. Tell me guys how I got trouble , it'll fly on the wing and not like a rocket and land at 1/3 throttle easy. Have any of you gone this heavy?