jim62

I started working on my reaction i'm at the point of thinking of a turbine I was thinking of king tech k100 has 22lbs thrust
it is the same size and weight as the k80 has 19lbs thrust . the reaction calls for the k80
dose anyone have a thought on this

TommyWatson

My Feedback: (1)

I flew both my reactions for years with the standard wire legs on grass, never had any trouble. Look at bruce's site and see the video under Watson.

highhorse

My Feedback: (2)

Fair enough. I will still use TL gear for two reasons:

1) Bob Wilcox (JetCat) advised a friend of mine that they were easier on engine bearings because every little bump in the grass wasn't instantly translated to longitudinal motion at the engine.

2) Boomerang Designer Alan Cardash's advice to mounting gear with servo screws - yes, servo screws - works quite well. Think of the screws as "fuses" which hold quite well until you really prang one HARD, and then they let go rather than transferring the load to the structure. I understand skepticism on the part of some, but this has saved my 40lb Boomer XL twice now. The screws always hold in normal and moderately bad landings, but have let go and saved the structure when by all rights i should have been on the hook for major repairs rather than simply CA-ing a couple of screw holes and installing new screws.

hollywood_07

My Feedback: (13)

Highhorse is right...I will fly off of grass 95% of the time.

afterburner

My Feedback: (18)

My Reaction was maidened in August of '06 with the wire gear. Once they got bent after a few not so soft landings, it was time for some struts and I used Robarts for the mains. I fly about 95% off of grass and have no problems. I do think that heavier jets will benefit more on grass with trailing link gear causing less stress on the mounts but the Reaction is fairly light and I'm not sure it will make any difference. Just my opinion from flying this battleship of a jet for eight years.

hollywood_07

My Feedback: (13)

Ok thanks Marty! May just stick with the stock legs for a bit then.

gsmarino2000

My Feedback: (2)

Rough measure with a fish scale, my K80G is producing close to 20 lbs thrust (on diesel). Regardless, the 80 and 100 are the same size and weight. You will lose a bit of efficiency running the 100 at lower throttle settings but not an issue if you have enough fuel capacity. In terms of stress on the airframe, shouldn't be an issue if you use the extra power only on take off and vertical climbs.

Mike06659

I think I was one of the first to install TL gear on the Reaction and they worked great compared to the old wire gear. I cannot remember exactly which ones, but they were Prolink and designed to fit one of the Boomerangs. I purchased them from Dreamworks

mr_matt

My Feedback: (10)

Mike did you have to change the wheel well locations in the wing? Do you remember what retract unit you used?

To me it seems like the reaction sets so low that none of the stock prolinks would work (but they are not that hard to shorten)

Thanks

Mike06659

Matt, I had to slightly enlarge the wheel-wells a little and then I made new side wells if that makes any since. This was all done after a couple years of flying on the stock gear and I believe they were Robart retracts. Whatever came with the original kits. You are correct, I thought the Reaction set too low as well. If I had to do it over again I would get the taller gear and just start hacking a little balsa It would give it a nicer stance.

Square Nozzle

My Feedback: (1)

According to my marked up plans, when I installed Pro Link gear I moved the wheel well inboard (towards the wing root) 3/8" to accommodate the longer gear in the relaxed position and rearward 1/8" to allow the wheel to center in the well. With load on the gear, the height of the plane remains about the same as the wire or robo struts.

joeflyer

My Feedback: (48)

John,

Are you referring to the Reaction ARF Prolinks? I bought the Dreamworks Reaction ARF Combo Set to use on my kit built Reaction. I'm about to start building and will be laying that out in the next couple of days.

Did you modify the main mounts much?

Joe

mr_matt

My Feedback: (10)

Same question John, what exact prolink part number did you use?

Square Nozzle

My Feedback: (1)

You had to ask!! I'll have to do some research to get the ProLinks that I used. I do recall that I turned down the top of the strut to get a deeper engagement into the Robart trunion.

Joe, I didn't use Reaction ARF Pro links. I believe they were struts (only) for the small Boomerang. The retract mechanics was the Robart gear that they made for the R-54.

siclick33

I've just received my Reaction kit and It looks great. Very well packed and the manual looks very well done. I'm looking forward to getting round to this as soon as the building backlog clears!!

There's a post from Bruce earlier in this thread that says that the Reaction ARF Pro-Links are longer than the kit legs.

mr_matt

My Feedback: (10)

Yes it is difficult to source prolink (or any) trailing link gear that short. For some reason the reaction has crazy short main gear legs.

siclick33

The ones for the Boomerang Nano are quite short and that is what I am thinking of using.

Square Nozzle

My Feedback: (1)

Matt, I measured the Pro Link struts I used and they are size for size with the struts for the Boomerang Nano. DreamWorks number PL11340. As I said, I had to lengthen the 7/16" diameter portion of the strut top to get full engagement into the Robart retract trunion.

mr_matt

My Feedback: (10)

Thanks John and siclick33

oliveDrab

I've seen several posts where guys have used a K80 or higher on the R54. Why not use the Jetcat P60-SE as recommended by Bruce?

BruceTharpe

My Feedback: (1)

oliveDrab, all due respect, but that's like asking why guys put a .60 on a .40-size plane. Modelers have loved power since the invention of power. There are some jet guys who look down their noses on jets that have less than 1:1 thrust, and that's too bad. When I test flew the R54 over a decade ago with a RAM 500 putting out 11 pounds of thrust (when it started), it was breathtaking. Then I went to 14 pounds of thrust and it was even more eye-popping. I think any new turbine pilot would be pretty darn happy with a P60 on their R54. More experience pilots gravitate towards the higher-thrust choices and I'm just glad the R54 has pretty well proven itself to be up to the task.

One other point... think about what would happen if I recommended up to 22 lbs of thrust. I will leave it at that.

afterburner

My Feedback: (18)

I flew my Reaction with a P-60 for about six years and then a JC Rabbit I had in another jet became available. Going to 19 lbs of thrust really made the Reaction come alive and feel like a new jet. I would recommend something in that range as it will work in a larger selection of jets if you decide you want something else down the road although whenever I think about getting rid of it for a different jet, I come to my senses and realize this jet can fly from just about any field and it's practically maintenance free. Other than the eight year old Monokote starting to get brittle and flaking off I've only changed tires for the most part.

oliveDrab

Right...........P-60.

BruceTharpe

My Feedback: (1)

Marty, you make a good point about considering how you might use your turbine in the future. A few of the guys who tell me they plan to use a K80 say that specifically, and it makes sense. Buying even one turbine is a pretty hefty investment for a lot of us, so you should think ahead. Look, we all have our preferences, and I readily admit to being a worry wart when it comes to overpowering any of my kit designs. But from what I've seen and read, all the builders who have gone with a higher-power turbine (18-22 lb. thrust) seem to have a good head on their shoulders and know how to fly with common sense. If "massive vertical" is your thing, more power to ya!

BruceTharpe

My Feedback: (1)

"I'm not crazy. My mother had me tested." Sheldon Cooper

Hey Matt, it sounds like you've received some good advice. Sorry I'm not more help on this, but I'm going to look into this some more and really try to nail down the best alternative struts. For the record, one of the main design goals of the R54 was to keep it as affordable as possible for a turbine model. The Robart retracts with wire struts were chosen with that in mind. But wire is wire, so the strut length was kept to an absolute minimum to do the job without needing to be bent back into position after every landing. Overall, I think the wire struts exceed expectations and work really well. There's a notion that the wire struts do not provide any shock absorption. Well, they do have loops that allow them to flex aft, and the soft Sullivan wheels provide cushioning that you don't get from hard (and expensive) "jet" tires. Just thought you might like to know the thinking behind some of my design choices.