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Reaction 54 Jet Kit

Old 04-25-2018, 11:15 PM
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Fuse sides, I'm omitting D2, it is the try for the ECU, instead I will be adding there a 16 oz. Nelgine bottle to increase flight time up to 10 minutes + 2 go arounds, the UAT is going to placed forward from the 16 oz tank.
Old 04-26-2018, 09:26 PM
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Fuse sides almost done.
Old 04-27-2018, 01:39 PM
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More fuse work.
Old 04-27-2018, 04:47 PM
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More done today, running out of mid CA glue

Last edited by CARS II; 04-27-2018 at 04:52 PM.
Old 04-27-2018, 06:45 PM
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The building had to stop early today, here is the reason why.

Last edited by CARS II; 04-27-2018 at 06:48 PM.
Old 04-28-2018, 03:44 AM
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Now You Are Talking. You are due a couple of hours "OFF" - Smiling. Chic
Old 04-28-2018, 05:30 AM
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I know it is very off topic but it was getting a little too repetitive, build, build, build, post, post, post.

Ok here is another picture of the fuse.

Last edited by CARS II; 04-28-2018 at 07:00 AM.
Old 05-01-2018, 12:11 AM
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I trimed mine sunday. Not a lot to trim, it fly straight. .. I know it's hard to believe, but to fit my particular taste I'll have to move the CG a bit backward by reducing the weight of the batteries

Last edited by SALMONBUG; 05-01-2018 at 01:31 AM.
Old 05-01-2018, 05:30 AM
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No, not at all, we all do that, jets fly better with a forward CG.

What I like to know is if there are any pitch changes when accelerating from half throttle to full.

Last edited by CARS II; 05-01-2018 at 06:32 AM.
Old 05-01-2018, 11:39 AM
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Originally Posted by CARS II
No, not at all, we all do that, jets fly better with a forward CG.

What I like to know is if there are any pitch changes when accelerating from half throttle to full.
Well, in my case I noticed a slight trend to pitch down ( but very slight ) using the stock turbine " tilting" wood part. But my opinion is that the effect will vary according to your cg position and engine selection and I would suggest to make the first flight using the stock configuration and fine tune it according to your particular airplane config and your own tastes

aft cg in addition to make your plane more responsive, save some fuel also ) ( either if you don't modify the airplane weight).


Because a lot of people read this thread and they maybe don't know why "aft cg save fuel", I give the short explanation for those who want to know.
The stab produce a NEGATIVE lift to counteract the effect of the distance betwwen the cg and the wing "lift centrum". If you move the cg more backward, the distance is less, meaning the negative lift generated by the stab to counteract the effect is less. Then the wing have to produce less lift ( the total lift the wing has to produce is the sum of the weight and the negative lift of the stab). If the wing has to produce less lift , it produce less drag. Meaning you save fuel........
I admit that in the case of rc jet , the difference is very small, but in airliners that's something we take care off to reduce trip fuel

because of my bad knowledge of english you maybe don't understand my short explanation, in that case just type " aft cg save fuel" on google and you will have the explanation in your mother langage

Last edited by SALMONBUG; 05-02-2018 at 01:01 AM.
Old 05-01-2018, 11:21 PM
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Thank you for trying, its all good, I understand, I think, got it, CG forward/bad. CG aft/good, got it.

Let us know if the change of CG helps with the slight down pitching.

Tks,
Old 05-02-2018, 12:44 AM
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Originally Posted by CARS II
Thank you for trying, its all good, I understand, I think, got it, CG forward/bad. CG aft/good, got it.

Let us know if the change of CG helps with the slight down pitching.

Tks,



My decision to move the cg a bit backward is definitly NOT a attempt to correct the pitch changes induced by turbine trust management. If I move the CG a bit backward , it's to have a more responsive airplane. The effect of moving the CG backward will make the airplane more sensitive to pitch change induced by turbine ( if there is one) in my opinion

When you decide to move a CG backward, be carrefull and proceed with several step by step tuning, because this change the airplane behaviours

So my suggestion to tune your R54 to your particular taste is to proceed like that

1) set the turbine tilt to stock position and the cg in the middle of the cg margin for the first flights
2) tune your CG to make the airplane matching your particular taste and skills ( I suggest to remain in front of the aft cg limit)
3) finaly make the turbine tilt correction if required

This is only my opinion and maybe Bruce should knock a the door to give his opinion on the subject

I'll let you know the correction I will apply on the turbine tilt if I make one. The nose down effect I felt was so small that it need to be confirmed after some other flights before I decide to put one or two washers to correct it

Last edited by SALMONBUG; 05-02-2018 at 09:43 AM.
Old 05-02-2018, 05:04 AM
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Here is a view of my finished inside setup. In order to remain in the "adfordableé" philosophy of the design I solved my need of 10 chanels ( i like to have all the elements on a separate channel) by making a twin receiver setup instead of serial bus or powerbox system.
The "front receiver is in charge of everithing except the gear stuffs. The second receiver is in charge of gear extension control, brake and steering.

I made a effort to separate gear and brake power supply from the main power suply ( just in case) and as you can see there is a connection to place a second lipo in parallel with the ecu lipo during start.
each receiver is fit inside a homemade 3D printed receiver case.
the two wood plate in the front are there to hold batteries firmly in place. Because I turned without lead I need to be able to move my batteries easily to modify cg, those two bolted wood parts hold them in place
I consider this setup reliable, but Of course I have what I consider to be a weak point. Either the ecu and pump "floor" is held in place with six screws, a steering servo issue would be extremely anoying and would require to disconect nearly everithing.....

Last edited by SALMONBUG; 05-02-2018 at 06:27 AM.
Old 05-02-2018, 06:32 PM
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After a good day of flying is time to go back to the building board.

It is really nice around here now, 80's and light winds for the next few days, the only thing that is bothering me are the allergies

Last edited by CARS II; 05-02-2018 at 06:36 PM.
Old 05-02-2018, 08:57 PM
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same here in belgium, hot temperature, and too much pollen in the air. Yesterday I let my car on a parking outside for 4 hours and when I came back it was literaly green from pollen dust. I suffer asthma and it's really not a good period for me

Last edited by SALMONBUG; 05-02-2018 at 09:56 PM.
Old 05-02-2018, 10:00 PM
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Fuse bulkhead and stab base are on, it assembled very square and straight on its own, nice!

Last edited by CARS II; 05-02-2018 at 10:03 PM.
Old 05-02-2018, 10:54 PM
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I guess you have a precise idea of your building sequence, but maybe you forgot to drill your nose gear plate

Last edited by SALMONBUG; 05-02-2018 at 11:27 PM.
Old 05-03-2018, 05:59 AM
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Originally Posted by BruceTharpe
Joe, I strongly recommend balancing in the forward half (6" to 6.5") of the balance range for first flights. The R54 is okay back to 7", and in normal flight I don't think you would feel much of a difference. But I have sensed a bit of twitchiness/sensitivity on landing approaches with the CG at the aft end of the balance range. The approach feels much more solid with a forward CG. Add the weight and don't worry about it. Make it removable so you can experiment later by pulling some weight out if you wish.
Here's how Bruce responded to my CG question a while back. I started at 6.25" and then moved it to 6.5". Based on Brice's advise I didn't try going further back. It flies and lands fine just fine at that setting, about 75 flights so far.

Joe
Old 05-03-2018, 06:28 AM
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Originally Posted by joeflyer
Here's how Bruce responded to my CG question a while back. I started at 6.25" and then moved it to 6.5". Based on Brice's advise I didn't try going further back. It flies and lands fine just fine at that setting, about 75 flights so far.

Joe

thanks a lot for sharing that. I see that my idea of moving the cg backward a bit won't have a lot effect on the plane agility
Old 05-03-2018, 07:19 AM
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Good eye but look again once I get the retract I will drill the holes and it will get epoxied on.

Last edited by CARS II; 05-03-2018 at 08:56 AM.
Old 05-03-2018, 08:08 AM
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Old 05-03-2018, 08:18 AM
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I will share what hapened to me with this particular building. I builded my first wing with the booklet next to me and made a good wing. For the scond wing I decided to go a bit faster. I placed the parts in the assembly order on a table and jumped in the building leaving the booklet in a corner of the shop. I was extremely proud of this second wing panel looking even better than the first one. When I cleaned the aera I found laying under the parts table............ The balsa wing dowel block glued to his hardwood partial rib. AAAAAAARGGGGGGGhhhhhhh
A delicate surgery on the wing sheeting has been mandatory to place it.........
Old 05-03-2018, 08:55 AM
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I'm glad you got it fix, that's the beauty of building a balsa wood airplane, you can fix, change, add, modified all you want.

My build is not perfect, I've made about 4 mistakes so far, nothing critical and they got fix, I keep saying, the next Reaction build is going to be flawless.

Last edited by CARS II; 05-03-2018 at 08:58 AM.
Old 05-03-2018, 09:15 AM
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there is only one kind of people that never make mistakes. The people that doesn't do aything
Old 05-03-2018, 09:00 PM
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Moving forward with the engine mount, used 30 min epoxy here.

Last edited by CARS II; 05-03-2018 at 09:46 PM.

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