BruceTharpe

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Mike, there is a sketch for the inlets on page 24, post 586.

As for CG, most guys like it towards the FORWARD end of the range, 6" to 6.5" from the LE at the wing root. It flies fine with the CG a little more aft, but landing approaches can get a little squirrely. If your elevator seems ultra sensitive during the landing approach and flare, add some nose weight.

There is a wealth of info on this thread, but it can be hard to find in the 100+ pages. That's why I created the "RCU Reaction 54 Thread Index" which lists the most helpful posts, broken into different categories like airframe mods, retracts and struts, fuel systems, etc... All R54 builders should bookmark the index - here's the link:

http://www.btemodels.com/r54threadindex.html

Mike06659

Sounds good Bruce and I wanted to thank you for designing such a great jet. After I took my first flight I asked myself what I was so worried about. It flew great!!!!!!!!!!!! It caught so many eyes at my club because they are use to seeing jets fly at such high speeds where the R54 can be slow and relaxing to fly. I demonstrated the whole flight envelope and they were in shock.

Have you ever thought about offering a second wing design for the current R54s flying. One that would be swept, thinner, and offer more speed and manevability? It would have the same mounting dimininsions as our current R54 but that's where the similarities end.
Just a thought.

Anyway, thanks again I really enjoy this bird.

Mike

BruceTharpe

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Thanks for the compliments, Mike. Glad you're part of the Reaction family

Sure, I've thought about alternate wings for the Reaction. But thinking is the easy part! Nothing in the works, but it is an interesting idea...

ww2birds

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Bruce,

Just think .. if you redid the wing, perhaps a little thinner airfoil, a little sweep, and an option for winglets or wing tanks (fiberglass parts .. interchangable .. attached with CF pins .. another accessory!) .. you would cover a lot of bases looks-wise and give folks a lot of choices. I think most of the kits come out needing a bit of noseweight, so you could afford a little wing sweep and just remove the weight.

One other thing ... if you look at the way a Skymaster F-4 fuse goes together, you can see that the intakes are attached to the rear of the two-piece fuse, and overlap the front part of the fuse. There is one bolt from the inside that secures the side of the intakes to the front fuse side. I'll bet you could attach inlets to the top of the modded wing, have them bolt on and get that mod included too. Then all you need is a modded hatch with canopy on top and you've got it all :-)

Plus, business-wise, you have enough Reactions out there you'd have a ready market to sell a bunch of them!

If most people are like me, they used the Reaction to learn jets, then instead of selling it and moving on, kept it as a favorite relaxing and fun sport jet .. so I bet most would go for another wing .. I sure would!

(sorry, can't help myself, I just love the darned plane!)

Dave

Gene Margiotti

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Bruce,

Just a note to let you know that I received my kit and accessories yesterday and everything arrived without any damage!

I know that this is old hat to the people reading this thread but I will reiterate that the kit, balsa and instruction manual are excellent quality!! I have to start building the kit now because I can't get all of the parts back into the box.

Really a great effort on your part!

I love to build and I really look forward to this winters' new project.

Thanks,

Gene Margiotti

causeitflies

The whole time I was building mine I was thinking about building another wing with some sweep, thinner airfoil and doing away with the nose weight. One day...

Mike06659

I just order some trailing links and wheels for mine. Our field is rough and beats up the wire gear so the upgrade is coming. I will let you know how the modification goes. Hopefully, it shouldn't be too bad. [8D] I'm on flight number eight and loving it!

DREAMER-RCU

EDF Reaction on final at AZ Jet Rally last weekend. Shows the approach angle (yellow/blue paint line) to be about 7 degrees.

knifeedgeyak

Hey guys,

This is probably in the thread some where but I am getting ready to tape my wing and was wondering what the best way to do it, as far at two pieces or one piece. Any thoughts would be great. I am excited to get the the next step. So far so good, for the most part.

Thanks,
Chris

TommyWatson

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I used two pieces, put on the glass cloth, Drill the holes for the wing dowels then install the dowels. I used Zpoxy.

Regards

knifeedgeyak

What do you guys think about this whole faa turbine thing boiling right now. It makes me nervious to buy a turbine. Hope I did not wait to long to get into them. It would suck if they banned them.

BruceTharpe

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Yeah, it would suck. I suppose it's possible, but I really think common sense will prevail. If anything, the possibility makes an even greater point for getting a turbine now. I don't want to sound snobby, but I feel that flying a turbine model, even a lowly R54, is the pinnacle of our hobby. If you miss out on that, it would really suck.

knifeedgeyak

Well I have my wing built and ready to tape. It came out pretty good. Not as nice as some of the builds I have seen on this thread but I think it should work. I am just saving my pennies to buy the flame for the plane.

knifeedgeyak

How do I put in a picture? I can not figure it out to save my life.

bobparks2

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click on the "post reply" button below the last post, or the little "reply" icon in the upper right above a post. Do not use the "fast reply" at the bottom of a page full of posts.

Once you are in the "reply to message window", just below the box where you enter your text, there is a link "click here to upload images and files"

bob

knifeedgeyak

Here is the wing. Not as pretty as you guys builds but it should work great.

Pitts S1S

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OK Here is something new for you 54 devotees

Built a 54 for a friend in Florida, but he doesn't like fighting with large wings, who does. So after calling Bruce for some support (Thanks Bruce!) This is what I ended up with. The pictures should explain it all.

Pitts S1S

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Some More

Pitts S1S

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More

bobparks2

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without knowing the details on that carbon joiner tube, its hard to say for sure... but the ultimate strength of the wing is probably greatly reduced from that of the normal wing.

Now, the normal wing is REALLY strong, but an R54 can hit 150 mph, and with that big wing, if you had enough elevator authority to stall the wing, thats probably over 1000 lbs of lift (50 G loop, about 60 ft diameter). The elevator is a pretty small chord with a large fixed stab, so that will limit the pitch rate and thus the G's. (i.e. there is plenty of elevator to stall the wing in landing flare, but not enough to stall it in a high speed loop where it also has to overcome the pitch damping of the fixed stabilizer. A full pivoting tail would not have this inherent safety feature!)

The stock wing is probably good for about 12,000 inch pounds of root bending moment. Thats about 1500 lbs of wing lift, so a nice safety margin.

Looking at your photos, you have about a 1" OD joiner. It depends on how thick the wall is and what kind of layup (mostly unidirectional or woven) etc, but even uni carbon with a .05" wall thickness would only be about half as strong as the normal wing. A woven joiner might only be 1/4 as strong as the basic wing.

So, it would still be good for 15 G's, and thats plenty for "jet like flight" but I would not suggest entering it in the "who can do the tightest high speed loop" contest!

Note, all of these are REALLY rough "back of the envelope, too early on a Saturday morning" number, but they are probably not too far off.

Bob

Pitts S1S

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Bob,

The wing tube is 1.25" Aluminum, anodized black, the rear wing tube is 3/4" Alum.

I built them as close to the main spars as I could to utilize some of the spar strengh, and disperse the load on landing. The rear tube phenolic is actually hysoled to the web shears on the rear spar. The front tube is 1/4" forward of the main spar. Plus all the ribs have 1/8" Lite ply doublers at the tube locations. The 4 ribs at the joints have 1/8" Hard ply doublers. The main tube is 48", and the smaller tube is 32".

Does that change your calculations any? I built it to withstand what I thought would be reasonable landing loads, thinking this is where most of the forces would be generated for bending.

Jeff

bobparks2

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Well, aluminum makes it easy to calculate. What wall thickness? As far as I know, all the RC joiners are 6061-t6 alloy. (pretty good and readily available). I figured the old Gator 1.25" OD, .035" wall joiners were good for about 1400 in-lb of moment, about 1/8 of what the basic R54 wing is good for.

Also, graphite is nice and strong and stiff and light, but its prone to a small local issue (point crushing, or local flaw) causing a premature overall failure. Aluminum is less fussy. Also, the aluminum will deform a bit before it breaks. If one day its hard to pull the joiner out and you notice its not straight anymore, thats a good warning that you have been pushing the model too hard!

The rear joiner wont carry much bending load, because its so much more flexible than the front joiner. Even if its the same wall thickness, its only 20% as stiff as the main joiner, and its probably thinner wall. I would ignore it in the rough overall load calculations and just call it a bit more safety margin.

That makes the wing stiffer, but not stronger. Where the panels join, ALL the load is in the joiners, since there is no spar. If the joiner fails, thats it... you have a nice strong outer panel fluttering down somewhere..

I noticed that in the photos. Thats a good way to do it. The issue with joiners is that you have to get the bending loads that are in the skins and spars to transfer into the joiner. The best bet is to build the joiner into a box spar, but what you did is a good solution for the R54.

Thats probably far longer than it really needs to be. The longer the joiner in the lower the loads at each end to transfer the bending moment in and out. If you do a really careful design and construction, you can use a much shorter joiner, but usually, its not worth the hassle. (i.e. if the joiner has 1400 inch pounds of moment in it, that means a vertical load of 100 lbs 14" out from the root or 200 lbs 7" out, or 700 lbs 2" out. They all work, but 100 lbs is easy and 700 lbs is pretty hard to handle)

The problem is that the R54 has a huge wing, pretty light wing loading and an airfoil that can make a lot of lift. Its also clean enough for a turbine to shove it through the air pretty fast. So **IF** you have enough elevator authority to get the wing up to its stall angle of attack at that high speed, you get a HUGE load. As I mentioned, Bruce set up the R54 with a big stab and small elevator. Its got plenty of authority to stall the wing in level flight (which you want, so you can do full flare landings), but it makes a lot of pitch damping to limit the elevator effect at high speeds. (think of it as automatic dual rates!). I really cannot just look at this and guess what the high speed elevator authority is. ( I would need to spend an hour or two to do that analysis). So, the reality is that the peak loads in flight are going to be a lot less than the high speed stall load.

If you have a .035" wall joiner, thats good for about 10G's, which is about a 300 ft diameter loop (or pylon turn) at 150 mph. Thats about 4 seconds to complete the loop, so actually kind of tight for "smooth, jet like" flying. And if you just slow down a bit, the loads go way down too. (100 mph is under half of what it is at 150)

Landing loads are really hard to estimate.. besides, whatever estimate you make, some pilot will just manage to land it even harder still! The joiners you have should be just fine for any reasonable landing, and, as I mentioned, they will just bend a bit in a rather unreasonable landing.

BTW, it can be pretty reasonable to split the wing at the flap to aileron junction. The loads are down to about 1/8 of the root loads, and you dont have to disconnect the pneumatic lines in so many places. I wish I would have done that on my wing! Too late now.

Bob

ww2birds

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FYI, I have the RCATS telemetry system in my R54, and "normal" smooth flying, with some sorta tight turnarounds, and standard aerobatics, gets to 6-7 Gs according to the RCATS system. If we ever get any warm weather ever again I could see what it does with more aggressive flight... this was according to the analog g-force sensor, not the GPS.

I also discovered that the GPS in the RCATS system has to "lose lock" and not report coordinates if the acceleration is over 3Gs .. apparently that's to make sure it can't be used to build guidance systems or other "scary" stuff...

Dave McQ

edit: removed typo on eagle tree, that's another plane

bobparks2

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That sounds about right. You can do pretty tight as long as its not out of a full throttle screaming dive. I would not trust the RCATS or Eagle Tree GPS for highly dynamic maneuvering anyway, they are not fast enough.


I am not sure on that. There are limits on altitude and speed combinations, something like over 500 kts while over 60,000 ft. The rule is that the GPS has to cut out when both conditions are true, but some GPS just cut off with altitude (In spite of the specifications claiming otherwise.. I have encountered 2 different GPS that cut out at 60K at lower speeds. The first one was in flight, the second was in a GPS simulator since we at least learned that we had to test regardless of what the specs said!)

Anyway, getting a GPS to handle a lot of G's and tight RC model type maneuvers is hard to do, and thats just likely to be left out of consumer units due to the cost. i.e. you might need to have one receiver circuit per satellite to get all of them at once vs the low cost thing of one RX sequencing between the satellites.

Thanks for the data! Have you flown with the airspeed sensor hooked up? If so, what did you get?

Bob

bobparks2

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Oh yeah, the other issue for GPS in maneuvers is that one antenna cannot see the satellites when the plane is inverted! Even if mostly right side up, in a tight banked turn, it will see different satellites on one side of the turn than on the other, and its not going to be able to change lock that fast.

Bob