R/C BG Help

[aerostadt]

I am looking for help for an R/C Boost Glider that I got from the estate of Frank Hunt, who was an active UROC member and UROC NAR adviser. Frank passed away several years ago after making many contributions to the Club.

Attached are some photo's of the glider. I tend to think that Frank did not fly this glider and may have had commissioned someone to build it for him, although, I'm not sure, Frank might have also been a model airplane enthusiast. The wingspan is 31.75", however, with a Spektrum AR0400 receiver, two HS-55 servo's, and a 1s 3.7 v Lipo battery weighs only 6.5 ounces. I was thinking of setting the transmitter on acrobatic/dual aileron, but I noticed that the transmitter has a sailplane selection, too. I am wondering where the CG goes on a plane like this. The motor pod takes 24 mm diameter motors. I am not planning to fly this until the weather gets warmer, but it would be nice to fly it sometime in 2018. Any advice would be appreciated.

 

[Onebadhawk]

I've got an easy one from setting up RC aircraft...
The centre of mass should definitely be directly under the centre of lift...
But the mass changes after the burn..
Split the difference..

Teddy

 

[KevinM]

Wow, that looks like something that was inspired by the Edmonds ARCIE. (I've built two now, this is the most recent.)



What transmitter are you planning to fly it from? How much RC experience do you have? I ask because your experience and the capabilities of your transmitter could affect the complexity with which you might like to set up the controls. Also, knowing the setup that works with an ARCIE you might not want to set this up with just basic aileron controls - some form of differential or false elevator control is probably a good idea.

What are the dimensions on your model? Wingspan, root chord (including ailerons), sweep-back, tail span, distance from wing LE to tail LE? Can you sketch up a quick drawing?

KMc

 

[burkefj]

Yeah, looks like the Edmonds design where you just have aileron for turning only, in this format if you balance for glide, the motor and pod are ahead of the wing LE by design so should be stable for boost, if the stack boost Cg is at or ahead of the le it's probably ok. It's light enough you can try glide tests for the glider cg Try this review, it shows a review of an arcie ii with cg markings and dimensions. https://www.rocketreviews.com/edmonds-aerospace-arcie-ii--by-bob-cox.html

 

[aerostadt]

Thanks for the advice everyone. I will check it out.

 

[kjohnson]

That is an original Edmonds ARCIE, the later one with the solid preairfoiled wing that KevinM posted was the ARCIE II. This version has a built up fuselage and a wing made from two skins over a row of ribs that were glued in a pattern like this /\/\/\/\/\/\/\.
There were very few of them kitted. Flies great on D12-3 and E9-4.

kj

 

[DuaneW]

That is the original Edmonds ARCIE. Rob simplified it for the version you have. I still have my mk. 1 version in the box.

 

[aerostadt]

I do have the ARCIE. It looks like I have the original version. I did sand an airfoil into the wing, but I tend to think that there is not much camber there. I cannot tell now, because there are wing tip fins glued on. There is definitely camber on Frank Hunt's red glider as seen in the photo. There is a bad tilt in the wing on my ARCIE with respect to the fuselage. Evidently, I did not glue the wing on straight. I read where some ARCIE fliers noted a death spiral due to perhaps a weight mismatch on the wings. Perhaps, some weight to one of my wings might correct for the wing tilt. Also, I need to revisit the engaging of the elevon horn with the wing tabs. I need to do trial tosses and check out the electronics, too.

 

[aerostadt]

OK, I have come back to this project after about a year of other distractions. It looks like I did not pay enough attention to all the good advice that I got here about this boost glider being of the Edmonds ARCIE design. Especially, KJ and Duane point out that this was something like the first ARCIE kit design. That is amazing, because this model looks so much different than the ARCIE II. The model is bigger and the wood is entirely different.

So, you can see how far off my thinking was from the attached photo's, because I've got 2 servo's crammed into the flight compartment. As I result the servo arms are very short and everything is going to be too packed together. So, from what everyone has stated about the ARCIE, I need to put in just "one" servo. Then I can balance the model like the ARCIE with the c.g. being on the wing (maybe somewhat to the rear of the wing) and getting a basically level flight. Then I set the Spektrum transmitter to Dual Aileron Wing connection to direct the model to the left or the right. Is that correct?

 

[MaxQ]

OK, I have come back to this project after about a year of other distractions. It looks like I did not pay enough attention to all the good advice that I got here about this boost glider being of the Edmonds ARCIE design. Especially, KJ and Duane point out that this was something like the first ARCIE kit design. That is amazing, because this model looks so much different than the ARCIE II. The model is bigger and the wood is entirely different.

So, you can see how far off my thinking was from the attached photo's, because I've got 2 servo's crammed into the flight compartment. As I result the servo arms are very short and everything is going to be too packed together. So, from what everyone has stated about the ARCIE, I need to put in just "one" servo. Then I can balance the model like the ARCIE with the c.g. being on the wing (maybe somewhat to the rear of the wing) and getting a basically level flight. Then I set the Spektrum transmitter to Dual Aileron Wing connection to direct the model to the left or the right. Is that correct?

If your ailerons will only act as ailerons (each one moves opposite of the other one) and will not need to also act in unison as flaps (down) or provide reflex (up) then yeah, only one servo is required.
One servo arm with a push rod on each end/side will move each aileron in the opposite direction of the other one at the same time.

I have the Arcie II...started...never finished it as I built the Aerotech Phoenix instead.
But still have the instructions.
The Arcie II has the servo battery and Rx in an open exposed bay in the nose and not in an enclosed fuselage. This allows the battery to be moved forward or backward to balance the glider.
Each wing has a diamond imprinted on the top surface, 3/4 of an inch out from each wing root edge, aprox. 2 7/16 inch back from the leading edge of the wing.
...that's where the balance point/CG is...….



​

 

[aerostadt]

Thanks Maxout.

I, also, have the Arcie II and along with the instructions. I know that I have flown it at least once with no success. It went into a fast dive and did not pull out. I did see a Arcie II perform well at a Hellfire meet several years ago, so I know that it can done. I am not sure the airfoil on my Arcie is very substantial. The airfoil on this current red glider is quite substantial, so perhaps that will help. I keep thinking of going back to my Arcie II, but so far I have not gotten around to it.

I have thought of cutting away the sides of the fuselage of the current model, so that I can extend the servo arms beyond the fuse, but I would have to cut away half or more of the sides of the fuse. I am not keen about this idea.

 

[Crawf56]

On my Arcie II, I used one servo for ailerons, and added a second servo for an elevator.

https://www.rocketryforum.com/threads/arcie-ii-rc-boost-glider-from-arkansas-edmonds.138600/

 

[MaxQ]

Thanks Maxout.

I, also, have the Arcie II and along with the instructions. I know that I have flown it at least once with no success. It went into a fast dive and did not pull out. I did see a Arcie II perform well at a Hellfire meet several years ago, so I know that it can done. I am not sure the airfoil on my Arcie is very substantial. The airfoil on this current red glider is quite substantial, so perhaps that will help. I keep thinking of going back to my Arcie II, but so far I have not gotten around to it.

I have thought of cutting away the sides of the fuselage of the current model, so that I can extend the servo arms beyond the fuse, but I would have to cut away half or more of the sides of the fuse. I am not keen about this idea.

Did not pull out of a dive......
Did it survive?
Was the CG correct on it?...sounds very nose heavy - were you able to do any test throws with t?

 

[aerostadt]

Did not pull out of a dive......
Did it survive?
Was the CG correct on it?...sounds very nose heavy - were you able to do any test throws with t?

It survived enough that I was able to re-build it. I thought I had balanced it correctly. As I said I may go back to it someday. I see on Rocket Reviews that flyers had made many good flights with the Arcie II. If and when I go back, I will do test throws. I may not have done test throws the first time.

I am re-looking at the two-servo's option on the red glider. I may be able to make some tweaks to make it work better.

 

[aerostadt]

That is an original Edmonds ARCIE, the later one with the solid preairfoiled wing that KevinM posted was the ARCIE II. This version has a built up fuselage and a wing made from two skins over a row of ribs that were glued in a pattern like this /\/\/\/\/\/\/\.
There were very few of them kitted. Flies great on D12-3 and E9-4.

Kj,
That sounds encouraging. Did you use one servo or two?

 

[aerostadt]

I finally flew this original ARCIE last Saturday on an E9-4. I had flown an E9 from this package at the previous UROC launch successfully, so I felt reasonably confident. The test hand launches in the back yard looked good. As the video shows the B/G red glider was near apogee when it shredded. The left wing came off. At the landing site the vertical tail stabilizers had broken off and the horizontal part was split part way.

 

[8thPaladin]

It was sad to watch in person. Hey, I'm in your video...

 

[aerostadt]

It was sad to watch in person. Hey, I'm in your video...

Mike, are you the one next to the LCO table? Yes, it was sad to watch. I was hoping that it would turn out good.

 

[8thPaladin]

Yep, white Hellfire 22 t-shirt

 

[aerostadt]

I got some foam cores from Matney's models on-line during the summer. I'm just getting around now to seeing if this model can be repaired.

 

[aerostadt]

I tried gluing the flat bottom of a foam core to 1/16" thick balsa wood with white glue, but the wing warped badly. Then I tried spray adhesive on a foam core and that melted badly. I was going to throw everything away and call it quits. However, I took what foam cores I had left and attached 1/16" balsa to the flat side with 5 minute epoxy. Then later I attached 1/32" balsa to the foam top side using West Systems epoxy. I am not sure how this project will turn out.

 

[JoeG]

I have used 3M Brand 77 Spray Adhesive for foam wing cores for years. Initial placement is critical since once the two surfaces touch there is no repositioning. The regular white and aliphatic resin glues need air to dry and take forever to dry on sheeting jobs. Epoxy cures nicely but can be heavy unless you get it on very thin.
All of these seem to have their advantages and drawbacks. Good luck.

I tried gluing the flat bottom of a foam core to 1/16" thick balsa wood with white glue, but the wing warped badly. Then I tried spray adhesive on a foam core and that melted badly. I was going to throw everything away and call it quits. However, I took what foam cores I had left and attached 1/16" balsa to the flat side with 5 minute epoxy. Then later I attached 1/32" balsa to the foam top side using West Systems epoxy. I am not sure how this project will turn out.

 

[aerostadt]

Well, eventually I gave up on both my Arcie and Arcie II and threw them away. I thought that I was done. Lo and behold, about 2 months ago I inherited the Arcie II again from the Fred Williams estate. Thanks, Fred, I will try to do good this time. Actually, Fred constructed his Arcie II much better than I. For some strange reason I kept my Arcie II transmitter, receiver, batteries, and instructions. I decided to replace the standard battery set-up with a very small Lipo battery. The batteries are shown in the picture below. The standard set-up is 20.16 g (or 0.706 oz) and the Lipo battery is 4.22g (or 0.149oz).

 

[aerostadt]

Well, Lo and behold, the UROC NAR Section competition advocates had a small section meet last Saturday and the Section had chosen E-motor Boost-Glide Duration as one of the events. So, I thought I would give it a try. Bruce Bell had his own scratch-built Boost-Glider that did very well with a qualified duration of about 1:09. Winds were very calm. Against some of my sworn statements to the contrary I used an E12-4 on my first attempt with no motor problems. After pop-pod separation the glider pulled into a glide right away. I used the standard set-up with no up or down control only left or right. I had some control, but not as much as I would like. A fellow flyer thought that there was a lot of stalls and poor gliding. He was right. I checked the balance point on the wings with the instructions on the bench several day before the launch and it was not right. I did a test glide in the back yard and thought it looked good, but that is a very short test. I will try to do a good balance next time. In any case I had a glide of about 44 seconds when one wing popped off just before landing. Upon landing the other wing broke off. Both wings broke fairly clean on the wing joint, so with some sanding, it can be repaired. I am including a picture of Bruce's scratch glider for reference. Bruce is the one in the wide brim hat.

 

[aerostadt]

Here is something that is puzzling me. The location for the desired c.g. of the Arcie II is shown both in the instructions and with ink markings on the wings just slightly forward of the ailerons. Even with the recommended batteries (about 0.7 oz given in post#23) the model is tail heavy. Today I used 1.07 oz lead weight in the forward position and got the model to balance at the given c.g. location. (see picture below). This is more than the standard battery weight. Does this sound correct?

I hand tossed the glider twice in the back yard and it did glide, but I didn't feel good with that much weight. There is a paper tube shroud (BT-50?) that goes over the battery, receiver, and servo. I am wondering maybe if I could make a longer shroud and put the battery in the far end I could move the c.g. forward. However, trying this strategy with the small 1S Lipo battery (0.15 oz) probably won't do much good.

 

[Ez2cDave]

Here is something that is puzzling me. The location for the desired c.g. of the Arcie II is shown both in the instructions and with ink markings on the wings just slightly forward of the ailerons. Even with the recommended batteries (about 0.7 oz given in post#23) the model is tail heavy. Today I used 1.07 oz lead weight in the forward position and got the model to balance at the given c.g. location. (see picture below). This is more than the standard battery weight. Does this sound correct?

I hand tossed the glider twice in the back yard and it did glide, but I didn't feel good with that much weight. There is a paper tube shroud (BT-50?) that goes over the battery, receiver, and servo. I am wondering maybe if I could make a longer shroud and put the battery in the far end I could move the c.g. forward. However, trying this strategy with the small 1S Lipo battery (0.15 oz) probably won't do much good.

Yes, moving the battery forward is a great idea. Any additional mass will only have a negative effect on glide performance.

The ARCIE II appears to have a short Tail Moment, something I try to avoid, personally, because such gliders tend to be very "twitchy" and can be very finicky to trim.

https://www.amaflightschool.org/getstarted/how-do-i-understand-basic-aerodynamics

https://www.rcgroups.com/forums/showthread.php?614774-When-Is-The-Distance-Between-Wing-Tail-Too-Short

The attached PDF file has some very good information . . . ( image from it below )

Dave F.

 

[aerostadt]

Going back and looking at the Arcie II, I think the tail boom going from the design c.g. is quite long about 12" and the tail itself is quite large. So, some forward weight is necessary to bring the actual c.g. to be aligned with the design c.g. (Also, the tail/main boom is heavier than balsa, perhaps, basswood) Actually, the wings are swept back and the author (Bob Edmonds) states in the instructions that the ailerons are slanted down slightly to contribute to lift. Taking all that into account the projected mean wing chord onto the root chord is probably about where the design c.g. is located. So, although, I was originally surprised about the c.g. location being so close to the forward ailerons, it is probably not unusual. I think Bob Edmonds is probably placing the design c.g. about at the center of lift, so that the movement of the only one servo to control the ailerons controls the left and right turns. The instructions do state that the glider will probably tolerate a wide range of actual c.g. I weighed my receiver and found that it is only 0.278 oz. Thinking that I would like to match the design c.g. I made the nose cone housing tube an additional 3.75" longer than the original. I then moved the lipo battery and the rcx forward, so now the actual c.g. and design c.g. pretty well match. Doing some glides in the back yard I can't tell much difference in the gliding performance. I will need to fly this with a motor to see how well it works.