BruceTharpe

My Feedback: (1)

Use the short horns ( 3/4" ) for the flaps, long horns ( 1-1/8" ) for ailerons.

flyinfool1

My Feedback: (2)

Woo Hooo.
I finally got a CD, a waiver holder, work, weather and other distractions to come together and made my first turbine flight last night.

I had to bring my R54 to work with me and worry all day about it still being in my truck after work since I work in a very slimy neighborhood and have to park in an unattended parking lot out in the open.

Then I had to blast out of work right at the bell to make the 20 mile drive to the field, assemble and prep the plane.
Calm down the jitters for a couple of minutes.
I finally broke ground about 10 minutes before sunset.

The flight its self was nothing spectacular, trimming then some slow flight and check stall characteristics, a few laps around the field with a few loops and rolls thrown in, and an early landing just in case it would take a few trips around the field to get it right. Didn't need the extra trips since the R54 just settled right in and touched down nice and soft right in front of me.
Flew for 5 minutes and still had about a third of a tank of fuel left over.

Now I just need to get everything to fall into place at least one more time to actually get signed off on my waiver.
Then it is burn kero time.

Thanks to everyone that I made crazy helping me to get this far.

BruceTharpe

My Feedback: (1)

Congrats Jeff! That first jet flight is always special for the pilot, no matter what the jet model is. Hope you enjoy many more!

flyinfool1

My Feedback: (2)

Thanks Bruce.

Now if I can just get the weather to cooperate.

I do have to admit that I was pleasantly surprised by just how fast the roll rate was and how tight it could loop and turn without even getting close to a stall.
I guess I was expecting it to wallow around the sky like most of the jets I have seen fly at our field.

I do intend to abuse this plane in the air since my head will explode if I fly straight and level for more than a couple of seconds.

Me thinks me has a keeper here.

mr_matt

My Feedback: (10)

Hi Jeff,

Great to hear about your success, did you go with the P-70? And you used the Garry Mueller tank if I remember correctly?

Also, has anyone tried a set of trailing link main gear in a Reaction? I would like to fly off of grass this gear design is very interesting to me and I would like to try it.

Thanks in advance,

flyinfool1

My Feedback: (2)

Yes I have the kero start P70.
I am not sure about the brand of tank since I can barely see it.
It is Kevlar and rectangular.
I bought this plane from Samo here on RCU, there are some pics ind info about it earlier in this thread. Look around post 1342.

My first flight was off grass as will be all of my flights.
I do have the stock mains. So far after one flight nothing fell off.

I don't know of a paved runway within 3 hours travel. so unless I go to a jet meet somewhere I'll be off grass.
The nose gear is the one I am worried about.

BruceTharpe

My Feedback: (1)

Matt, I whipped over to my handy thread index at http://www.btemodels.com/r54threadindex.html and found two possible posts that may help. Check out:

Post #1402 http://www.rcuniverse.com/forum/fb.asp?m=5296256
Post #1781 http://www.rcuniverse.com/forum/fb.asp?m=6205815

Square Nozzle

My Feedback: (1)

I'm in the sanding primer stage of finishing my R54 and will be installing the fuel components soon. This raises a question regarding the main fuel tank orientation as shown on the plans. Probably Bruce can put some insight into this. Why is the clunk in the main tank placed in the front of the tank rather than the rear. It would seem that in a steep climb the fuel will stay in the rear of the tank and the clunk will suck air.

BruceTharpe

My Feedback: (1)

Reverse the tank/clunk if you wish; a lot of guys do. Then you will suck air when in a steep dive. I've not been convinced that it makes any difference; the hopper tank (UAT) is supposed to keep air from getting to the turbine.

Kevin Greene

My Feedback: (85)

Hey Bruce---Any thoughts of a P-80 size R-54????---If you do come out with one or are planning one I'll gladly submit my deposit!!!---Design it with the inlets as some have added to their 54's and maybe a slightly swept wing.....[sm=thumbup.gif][sm=thumbup.gif][sm=thumbup.gif]

Kevin

samo

Jeff,

The tank is a 72 ounce Jet-Tech.

Andrew

speedbrake

John,
I agree with Bruce, it doesn't matter which way the tank is facing. I have two R54's, one has the tank facing rearward and the other the tank is facing forward. Neither one has caused any problems. The one with the tank facing forward was done so the fuel lines could go into the forward fuselage area under the canopy. I placed the UAT under the canopy to place all the weight forward. I talked with the PST representative about this topic and he agreed with Bruce. It's just a matter of convenience and how you plan to plumb the fuel lines.

Good luck,
Keith

speedbrake

Bruce,
I'm not sure about a P-80 size R54 but a swept wing version would be awesome!! Would your workload permit some design drawings for a swept wing option?
Keith

Woketman

My Feedback: (6)

I disagree about which way the tank faces. When the clunk is aft you only risk it being out of the fuel when the nose is downwards. But many times we are accelerating downwards (not always, but sometimes) and so the fuel may be around zero G. But when we climb, the fuel is ALWAYS at the rear of the tank. In other words, you can increase the safety factor on your header (how close you get to sucking bubbles) by using a rearward clunk or you can compensate by having a much larger header (dead weight).

In an old Isobar, I managed to get the clunk heavy enough on very flexible Tygon where it would go to all corners of the tank anyway, in all attitudes.

bobparks2

My Feedback: (1)

Woketman,

On a long downhill, the fuel will probably go forward. Its only zero g if thrust is greater than drag, i.e. the net acceleration is more than the 1 G of gravity. But the drag goes up in a hurry as the speed increases, and the thrust goes down a bit, so unless you are doing really absurd power dives, the fuel ends up in the front of the tank.

OTOH, if you do low power on the dive, the fuel flow rate goes way down. The main clunk will pull air, but not too much will get into the header because of the low flow rate. Combine that with the fact that there is not a lot of time on downhill, and its not bad.

For a climb, thats almost always high throttle, so high fuel flow rate, and you spend some time that way, so if you were pulling air in the main, then thats a lot of air in the header.

One final thing.. if the uphill or downhill is in a loop (i.e. pulling G's ) then the fuel ends up at the BOTTOM of the tank. It might have a bit more depth at the front or the back, but the whole bottom will be covered and the clunk will be submerged.

Summary: I do my tanks with the outlet at the front and the clunk mostly in the back.

Bob

afterburner

My Feedback: (18)

Whatever you do........PLEASE make it a two piece wing.

Marty

causeitflies

I had big plans (in my head, not on paper) of making a swept wing for my R54. It was also going to be thinner for more speed but about the same area. Maybe one day...

Woketman

My Feedback: (6)

Bob, yeah, that was my point. I realize that eventually on a downline the fuel will be forward, but for some of the time on some of the downlines, the fuel will not be forward. But its always rearward on the upline. So therefore it is better to have the clunk aft. Might not be a huge difference, but it's a difference!

Kevin Greene

My Feedback: (85)

I have to agree with you, Woket....I have a buddy of mine that bought a Byron F-16 turnkey at the local hobby shop with the tanks plumbed "backwards"....Kept flaming out with the tanks half full until until we found out that the tanks were plumbed with the clunks facing forward...Perhaps ducted fans are more sensitive to interuptions in the fuel supply but I wouldn't chance it with a turbine...Depending upon the UAT to smooth out the fuel interuptions is taking a bad chance in my opinion...Turbines cannot tolerate a good size bubble/interuption in the fuel supply---In my opinion, the only reason that you would not have a flameout with the clunks facing forward is that the UAT is doing its job in delivering a bubble-less fuel supply to the turbine...

Kevin

Woketman

My Feedback: (6)

Yeah, I like to give the header tank the best bubbless supply possible and make its job easy. Years ago (a long time ago actually, it was with a RAM 1000) I took the original Isobar (Eddie gave her to me and I fixed her up a bit with a nice coat of Kylon!!!) up with my own lost foam main tank and the pleated paper clunk header tank. I flew her dry on purpose and landed dead stick. Now, mind you, for the final minute or so of flight I was high up (keeping lots of altitude for the soon to come dead stick) doing lazy eights - no wild aerobatics. When I landed there was literally nothing but Jet A residue in the main tank (MAYBE two or three drops in a corner, when tilted for a minute or so), and a perhasp a half ounce in the header. THAT was what sold me on the pleated paper clunk!!!

causeitflies

Speaking of pleated paper pickups;
I don't use the pleated paper clunk, but I do use the pleated paper pickup in the hopper tank. In the F-16 I'm finishing up I also have it in a 10oz. tank (fed from two mains) which then feeds into the pleated paper hopper tank. Although the 10oz. tank isn't used as a filter, because it gets filled from the hopper tank, it still is a good bubble catcher for the main tanks. I used the extra long filter for this tank.

Woketman

My Feedback: (6)

I use just a big old cone shaped clunk in the main tank and a pleated paper clunk in the hopper. I use very flexible Tygon in the hopper to let it get just about all of the fuel it can get. Works great!

BruceTharpe

My Feedback: (1)

Well, several respected jet pilots have chimed in above in favor of a forward-facing tank/rear clunk setup, and I'm sure not going to argue with them. They all make a strong case. I know Dave Rigotti had flameouts with a forward clunk, none after reversing the tank (the 72 oz. kevlar tank), so there's a real-world example of the forward-facing tank/rear clunk making an improvement.

In my defense, I went with the rear-facing tank/forward clunk mainly because it simplifies and shortens the plumbing somewhat. It is an arrangement that was tested thoroughly before the release of the kit, and it never caused me any trouble. The prototype would typically land with the main tank about a quarter full, and the UAT never had an air bubble more than 1/4 its capacity. My second R54 also uses a rear-facing main tank/forward clunk, but the 16 oz. header tank faces forward with a rear clunk. In fact, the clunk is a pleated paper type inspired mainly by Wocketman's story (which I read somewhere else long ago). I described this fuel setup in posts 1556 and 1557 (photos too). It performed flawlessly all summer. Yes, air made its way into the header tank, but never more than 1/4 its capacity; usually much less.

I'm not trying to say "do it my way", but it does work fine if you want to. If you want to reverse the main tank, that's fine too.

Woketman

My Feedback: (6)

No doubt a forward facing clunk can work just fine. I just like the tiny bit of added insurance of having it the other way. A bit of extra plumbing though, as Bruce pointed out.

causeitflies

If your pickup line is very flexible it should follow the fuel wherever it goes, but I always put my clunks to the rear.