RCGUYS Super Decathlon

[RMS]

Hi,

I just purchased the RCGUYS Super Decathon. The specs are below.

WING SPAN 98"
LENGTH 66"
WING AREA 1558 sq. in.
FLYING WEIGHT 13-15 lbs.
RECOMMENDED ENGINES 90-160 2-stroke glow, 120-270 4-stroke glow
23-40cc gas
REQUIRED 4 channel radio & 6 servos min. 50 oz.in.

I originally was going to put my SuperTigre G3250 in it but since I have 36 A123 cells sitting on the shelf, I thought, "Hey maybe I will do this bird electric".

I'd like to power it with something that would fly it scale like.....with some reserve. Not like a "pattern ship J3 cub" that you see at the field every weekend.

I do not need any more than 7 to 10 minutes of safe flight time. The A123s charge quick and I have a field charger that can charge up to 50volts @ 20 amps. So battery configuration isn't an issue either.

I don't have the $$$ to experiment (I spent it all on the batteries and the plane). Can someone please suggest a motor/prop combo that will work for sure? I am sure I have clearance for anything up to 22 inches.

I don't have any experience with the calc programs. I usually use my watt meter and try different setups.....however, I don't have anything on hand for an airplane of this size so your help is greatly appreciated.

Not interested in the Rolls Royce of motors either. Budget for motor $0 - $200. If possible.

Thanks in advance.

[ScaleBrad]

Sure!!

I Fly my 1.20 Super Decathlon (discontinued Global ARF with some covering changes) on an E-Flite Power 160 Outrunner, at 16 lbs it's a rocket on a 10S 5300 Thunder Power Lipo. Swings a 20x10 prop. I fly for 10 minutes with plenty of battery capacity left. I get 20 foot takeoffs and then point it straight up for unlimited verticle. Or you can do scale takeoffs at 3/4 throttle. It will cruise easily at 1/2 throttle.


For your ESC needs try a United Hobbies 100A HV controller for $97 !!

I own three, only one in service at the moment, works great.

http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=4691



How about this outrunner for 10S lipo setup instead of the Power 160? you're on your own with this one though. I know the Power 160 will hold up to the power. $89.95 for this one

http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=5643

[RMS]

SCaleBrad,

Thanks for the response. I have been wondering why I hadn't received any responses. I thought this would be simple. That ESC is the one that I chose some time ago. I am glad you have had great luck with yours.

On my own, I had selected the Towerpro 5330-10t. I had not seen that monster motor you should me. I hope it is in stock. I will check that one out and hopefully get that one also...........I have more big planes to power LOL! It fits the budget.

Your airplane is a beauty!

Once this plane and the other few I have on the bench get completed, I will be doing the Nelitz J3 1/4 scale cub as a clipped wing version. If I am happy with the performance of the Decathlon (I will be), The Cub will go electric also. The A123 cells have made me reconsider electric for all my airplanes now. Especially the models that I put scale detail on.

Thank you again,
Rick

[ScaleBrad]

just posted video here:

http://rcuvideos.com/item/CM15GF80S7DVYHXR

2700 watts @ 16 lbs AUW ;)

[Geoff Dryer]

I am thinking about purchasing the RCGuys Decathlon and I am musing about what to power it with.

I have 6S-5000 batteries that I would like to use.

Dan at RCGuys weighed a Decathelon with servos but minus the motor and it was 11.25 lbs (5100g)

I calculated out the approximate weight of two AXI options including speed controller, BEC, and 5000 mah LIPO. The AXI 5345 is the only motor that will run 12S. AXI has a new 5320/18 that will run 6S

The AXI 5345/18 Combo (12S) weighs 5.7 lbs (2575g)
The AXI 5320/18 Combo (6S) weighs 2.8 lbs (1275g)

The plane with AXI 5345 and 12S would be 16.9 lbs (7675g)
The plane with AXI 5320/18 and 6S would be 14.0 lbs (6375g)

- The spec on the 5320/18 states a trainer up to 7000g
- Assuming I get the spec 1685 watts then it would be 120 watts per lb.
- They spec 77% efficiency at 1685 watts which is 1297 watts or 1.7 hp

These specs may be underrated as I am getting 1300 watts out of my 4130/16 in my Senior Telemaster and it hovers (10.5 lbs). I am using 6S.

Anyone care to speculate how the Decathlon will fly with the 5320/18 under 6S? I am looking for reasonable scale performance.

[jonnyjetprop]

.............deleted as I had the wrong motor..............

[Geoff Dryer]

The 5320/18 is a new motor designed for maximum 6S They claim
1685 input watts on a 18x12 propeller.

http://www.modelmotors.cz/index.php?page=61&product=5320&serie=18&line=GOLD

I have not found anyone who has tried it yet.

[jonnyjetprop]

I just found the specs on it: http://www.modelmotors.cz/index.php?page=61&product=5320&serie=18&line=GOLD

John

[jonnyjetprop]

Much better :rolleyes:


pitch speed of 70 mph
Thrust of 210 oz. (a bit over 13 lbs)

Yep, I say it should work.

John

[jonnyjetprop]

Any idea who's stocking the motor. I just called HL and they don't have it yet.

John

[Geoff Dryer]

I have not found anyone yet who stocks this motor.

Thanks for your opinion on this.

[karl k]

I'll be watching if Geoff gets one it will be the large scale flying partner for my big bush plane.

Karl

[DavidN]

You might find a Hacker A 60 s for that price on ezone.
I have an A60 22s which I picked up from Hacker as a demo used motor ($60 if memory serves). I am considering it for this plane. However I don't have ther ARF/servos/Rx etc.

DavidN

[Geoff Dryer]

I ordered the plane and other hardware last week.

AXI 5120/18 motor
Greatplanes Extra Large motor mount (unsure if this will work)
Hyperion 90Amp ESC
FlightPower EVO 25 6S-5000 battery
Castle Creations BEC
5 - Hitec HS645 MG servos
Dubro 6" balloon tires (tundra tires)

This should be an interesting build!

[RMS]

I'm glad this thread is still alive!!!! I have all my gear but no time right now to build it.

I went the thrifty route. This is my gear:

TP5330-10t outrunner
Turnigy Sentilon 100amp esc
Turnigy 15amp bec
5 JR DS821 servos
5 GWS 111oz/inch servos.....don't know what I will use yet
A123 cells...either 10s2p or 12s2p

I hope everyone posts their progress.

[Geoff Dryer]

Hello RMS;

Looks like your power should be slighlty more than mine factoring in the extra weight of your batteries.

I am aiming for something that is reasonably scale and nice and floaty.

Check out Karl K's conversion of the Lanier Husky (in this forum) He is using A123s.

[RMS]

I am all for scale flight. If it flies like a brick or a pattern plane it will get changed! I am hoping the large wing area can support the weight of the batteries. Nothing worse than seeing a cublike aircraft flying like a phoenix 60 or super chaos................Hmmmmmm that seems to be all you see nowadays.

[karl k]

Linky to my thread

http://www.rcgroups.com/forums/showthread.php?t=805272

Karl

[Geoff Dryer]

I noticed that the AXI 5320/18 is now on the Hobby Lobby site but it is showing late February for an ETA. I ordered my 5320/18 through a local supplier (www.pacificmodels.ca) although they do not have stock yet either.

My other parts are trickling in including the 6" Du-bro tundra tires. These tires are huge and also heavy 630 g (18.5 oz) for the pair but I expect that I will need this weight on the front of the plane due to the very light motor.

I don't yet have the plane. I ordered from Great Hobbies as they had the lowest shipping charges. They were not able to give me an ETA on delivery!

[Geoff Dryer]

Finally the plane has arrived and I also have most of the pieces except for the Motor.

Tentatively the electrification of the RC Guys Super Decathlon will include the following components.

AXI 5320/18 motor
Hyperion 90A speed controller
Castle CC-BEC
FlightPower EVO 6S-5000 battery (yes only one)
JR 790 PCM receiver
5 - Hitec HS-645MG servos
Electrifly extra large motor mount
Dubro 6" big wheels

My aim here is for light (to fly scale) but still aerobatic.

[VODOOFIXER]

This is a great electric converision. Last week we (Jim Kelso and me Al Messer) test flew and put a total of 10 flights on one. So I am able to give a first hand report.
First, don't use springs on the tailwheel streering!!!!! We did on the first day and went to a solid rod the next day, a must have!!!!
Second. Lots of aileron dif. You want all the up you can get and about 1/2 in. down.
I flew the first flight with no dif and would not fly the next one until we changed it.
With the dif it flys good you just have to rember that this is a short coupled high wing airplane it flys that way and when you make a turn you may have to use a little rudder.Just a little!!!!!!!!!!!!!! It takes just a little so make sure to use at least 50% expo on low rate rudder!!!
Power. This low cost electric flying.
HXT 63-64-B 230Kv about $60 plus shipping

TR S100A-hv-TURNIGY Sention 100AHV 2-12 speed Controller about $100 plus shipping

HXT G2 4100mah 5s 15-25c lipoly X2 about $95 ea. plus shipping

This combo will pull this ship srtaight up and is more power than you need but!!
We are running a 20-11 apce but have run a 22-12. The 20-11 pulls about 2200 watts and thats with cold batts. Its been cold here in wesrtern NV. And we are at 5000ft el. so at sea level it would be more.
Sorry to make this so long but it is a great project and it flys great with electric and when you make a low pass and hear the wind in the struts you will love it!!!
Al

[RMS]

Great report. I haven't gotten around to getting mine done. What kind of duration did you get?

[VODOOFIXER]

Most of our flights wer about 6 to 8 min. and we used 1700 to maybe 2300mah. This thing flys on way less than 1/2 throttle most of the time.
Al

[Geoff Dryer]

Thanks for the information VODOOFIXER. Right away I thought that the tail wheel mechanism was suspect. I think it would be better if the springs were heavier.

I also thought about aileron differential. I find it strange that no other reviews mention this.

[Geoff Dryer]

I have managed to get a little done on the Decathlon.

First off I cut out the covering for the various holes required in the fuselage and the aileron hatch holes in the wing. The clear layer of the covering seems to separate rather easily. I tried various temperature settings. I also re-shrank a few wrinkles but nothing serious.

Installing the main landing gear was a little tough as it is a rather tight space for the Allen wrench. I ended up carving a bit of plywood away with my dremel tool to make it easier to line up the wrench for the outside bolts. The bolts screw into the threaded gear. I managed to cross thread one of the screws so care is needed.

The tail surfaces were easy to install but removing the covering on the horizontal stabilizer was difficult. Again the clear layer of the covering pealed away easily leaving the color layer firmly attached. I ended up sanding it down the the bare balsa.

I replaced the hinges in the tail surfaces with some slightly heavier ones from Du-Bro. I though that the stock ones were a bit flimsy but maybe I am just paranoid!

I got the landing gear all installed and all the hinged surfaces glued in place. I noticed that the working door does not fit very well I may need to work on this a little before I glue the door on.

Next I will install the servos as soon as I pick up some servo extension leads.

[VODOOFIXER]

Geoff Dryer I would rethink the springs. A solid rod on one side works great and I really needed on a two of my landings last Fri. Takoffs where a snap, just add power and it goes but landings if it starts to veer you must have tight and positive control of that tail wheel. All of our landings where wheel landings but one. I was able three point that one. We where using low rate el. and I had the stick all the way back just as the wheels (3) touched, was great!
Al

[Geoff Dryer]

Not much available time this week but my AXI 5320/18 motor and batteries did arrive.

The GreatPlanes extra large motor mount is not quite long enough so I will have to back it with some 1/2 inch plywood. I drilled a couple of holes to attach the motor to the front of the mount. Unfortunately the plate is not quite big enough for the othe two bolts. A helpful member of our club is going to fabricate me an aluminum bracket.

I will have a spinner tomorrow which I think is the last component that I am waiting for.

[karl k]

You could buy a Power 160 x-mount and modify it to get the other 2 bolts to be holding the motor.

That should also reduce the amount of plywood needed to bring the motor as far out as it needs to be.

Can't wait to see this bird fly. I'm amazed at the number of large planes you have in your hanger and you don't even have a white cane ;)

Karl

[DavidN]

I like to use ESPRIT mounts; but i chunk of Ply is cheaper than changing

[Geoff Dryer]

I must have been having a blonde moment when I originally looked at the motor mount as I can extend it further. I received my MPI 3.5 inch spinner and it will work just fine. I fastened the motor mount to the firewall using blind nuts. I enlarged the hole in the middle for cooling and added two smaller holes.

[RMS]

I looked at the original picture and assumed that you had already tried it fully extended......This is good news! Now I can purchase this mount and it will work!

[karl k]

Looks good Geoff.

You've got to get into the air for the 2 man high wing aerobatic air show.

Are you back in town or just posting from abroad? You've missed a bunch of nice flying.

Karl

[Geoff Dryer]

I am back in town Karl. Of course the first thing that I did after returning was to work on my Decathlon.

A little more progress last night and now all the servos are installed. I also installed the horns in the ailerons. I am reworking the rods a clevis'. More on that later. I also ordered a 1/4 scale Great Planes pilot and wing bags from hobby-pak.com.

[Geoff Dryer]

I now have all the servos and controls installed.

[Geoff Dryer]

I am unsure of what scale extras to add but I knew I did want a pilot and dash. I found an image that someone had posted of a Scout dash (close enough) on RC Universe. I purchased a Great Planes 1/4 scale pilot.

[karl k]

Looks real clean and crisp, Geoff

Karl

[DavidN]

Looking really good.
Will you make it ti Chilliwack in May?

What weight are you at and with what battery?

[Geoff Dryer]

I am planning to be at all the Chilliwack events this year and hopefully the Decathlon will be finished for May. I do not know the weight yet but I was aiming for light which is why I am using the new AXI 5320/18 using 6S (FlightPower EVO25 6S-5000)

[Geoff Dryer]

Yesterday and today I completed most of the wiring and fitted the cowling.
The switch powers up the Castle BEC for the receiver and servos. The Deans plug shunt powers up the ESC. Next I will work on the struts.

[Geoff Dryer]

Struts always seem to be a pain to setup.

The first issue was that the pre-bent wire inter-plane struts were not correct. I was however able to rebend them without actually braking the wire. I had to repaint them afterwards.

The second issue was that the main front strut (that connects to the fuselage) was about 1/4 inch too long.

I decided that I wanted to be able to fold the struts down for transport. I decided to use wood inserts in the two strut ends that screw into the wing. I wanted a larger surface area so that it would not damaged the wing. I purchased some rubber grommets to prevent the bolts from loosening in flight.

I decided not to use the fiberglass cuffs. It seemed like a big pain to tape these in place each time.

It took me the better part of two evenings to get this assembled.

[karl k]

To have the wing fit into the bag, why not have the interplane strut lay down in the other direction (away from the wing root)?

Will the method of fastening the struts to the wing not allow that to happen?

Karl

[Geoff Dryer]

OK now I feel really stupid!

When I first tested folding it that way I swear that the servo linkage was in the way and it would not lay flat. It does work that way although it does not lay completely flat. Thanks Karl.

[Geoff Dryer]

Yesterday I installed the flying wires on the tail. I thought that the supplied clevises looked a bit out of place so I used some smaller metal ones.

I made the battery tray from some 1/8th inch ply and some blocks cut from 1/2 inch ply. I lined the tray with some thin high density foam (floor underlay). after assembly I epoxied the tray into place. I had predetermined an approxomate location. For balance I need the battery almost back to the rudder servo.

I also glued the door in place as I am finished installing all of the hardware.

[karl k]

It turns out not to be near as nose heavy as you thought it might be, eh?

That's a good thing. No lead in the nose needed.

Let me know when the maiden is.

Karl

[Geoff Dryer]

I was quite surprised that the CG was just about right without the battery. I would think that the AXI 5320 would be considerably lighter than a gas motor but I guess that all the weight of an outrunner is quite far forward.

After gluing the door it did not open properly :censored: I was able to unglue the hinges and I will try again.

[karl k]

Maybe the Du-Bro wheels helped with the CG? They are HEAVY! as I know.

Karl

[Geoff Dryer]

Tonight I managed to get the door glued in the correct orientation. I also altered the hole for the latch pin to make it close more snug.

I glued in the top window. I needed a weight to hold it in place (the fuselage sitting upside down). I will have to wait until tomorrow to let the canopy glue cure.

All I need to do is glue a few more windows in, reinstall the cowling, and then setup the radio. Getting really close!

[karl k]

Good news!!

Looks to be sunny from Monday on.

Shoot me a call when you are planning on flying it. I'll bring my camera and get a little video.

Karl

[Geoff Dryer]

Over the last couple of days I managed to finish up the Decathlon. I finished installing the windows using canopy glue. I needed to make an aluminum plate to complete the install of the motor to the motor mount. I also needed to make a washer to put on the back of the motor shaft before the collar. The collar is required when back mounting the AXI motor.

I setup the radio to the recommended throws. The CG was spot on 4 inches from the front of the wing.

I tested the motor and measured 1860 watts at 88 Amps (APC 18x12E)
This was the first charge on the FlightPower EVO 25 6S-5000 so I expected better more after a few cycles on the battery.


I am planning on a maiden for late Wednesday afternoon weather permitting.

[karl k]

Let me know when you are going to fly.

I'll bring the scales so that you can weight it before you fly and after so we can see how many electrons you used. :rolleyes:

If you don't have my cell number, let me know and I'll PM it to you.

Karl

[Geoff Dryer]

This afternoon I managed to get the first three flights on my Decathlon.

It was very windy but other than some long landings all went real well. We attempted to weigh it in the wind and it looks to be approximately 16 lbs including the 6S-5000 battery.

I did point it into the wind as much as possible on takeoff and the ground handling seemed OK. It is certainly not overpowered with this electric setup.
The first thing that I noticed is that you need to couple a litttle rudder to make it turn. I may put in some differential aileron to fix this. It flies very scale and whistles as it passes by. I started with completely neutral control surfaces and I think that I gave it one click of down trim.

On the second flight when I tried my first loop it did a snap roll instead. I think the wind must have caught it funny. It was very strange. Second loop was perfect. Inverted flight required no down elevator. Second landing was longer than the first. Unfortunately the wind direction meant that I had to maneuver around some rather nasty trees on the approach.

Video tomorrow after I do some editing.

My condolences to Karl who lost his Husky today in an apparent speed controller failure.

[karl k]

Feel free if you have time to post pics in my thread of the remains.

I won't be offended if you beat me to it.

A description of what you saw happen could help as well.

Congrats on the maiden.

Sorry to hijack the thread.

Karl

[Digiflier]

Congrats on the maiden of your Decathlon Geoff. I thought about going out to the field late this afternoon but noticed a nasty west wind and thought the better of it. Yikes, sorry to hear about Karl's Husky. Over amping the system or what?

lar

[karl k]

Not even close.
I've got the black box recording to prove it.

Max amps: 82.87
Min volts: 32.37
Cut-off voltage set at 24v
Castle 110hv controller

Karl

[Geoff Dryer]

Maiden flight video

http://media.putfile.com/Decathlon-First-Flight

[Geoff Dryer]

The weather has been west coast rotten so I have been able to fly the Decathlon again.

My wing bags did however arrive.

I bought two single wing bags from hobby-pak.com (2 X WBS01 $24.99). These are beautiful nylon bags with reasonable padding.

[Geoff Dryer]

I broke down and bought a digital fish scale.

Plane without battery: 14 lb - 1 oz (6375 g)
Flightpower 6S-5000 battery: 1 lb - 11 oz (760 g)
Total AUW: 15 lb - 12 oz (7135 g)

If I had used the stock wheels and wheel pants instead of the 6 inch Du-bro tires it would have been 12 oz (350 g) lighter.

[Tipover]

Geoff,
I've been eyeing your progress on this project, very nice build on a beautiful plane. Thats a great weight for all that wing aera, must be a real floater. Do you need to remove the aileron pushrod in order to fold the struts down? I can't make out whats going on in that picture.

I have a framed up(ready to cover) Dynaflite SD set up with a Brison 2.4. This RC Guys plane makes mine look real yucky(scale wise), and I'm now considering giving mine to someone and getting one of these to set up as an electric using A123's. After flying electrics for the last couple years I can hardly stand the idea of stinky gas. I suppose I could ship my Dynaflite uncovered ARF to someone in the same box this one comes in :D

Kevin

[Geoff Dryer]

Attached is a better picture of the folded struts. They don't go completely flat. Rather than undoing the aileron linkage I propped them up with a piece of foam. This should prevent any damage to the linkage. I intend on being reasonably careful not to stack anything on the wings.

In the video you can see how well it floats (forever) Once I get used to the plane I will slow it down more on the approach.

Good luck on the Dynaflite Decathlon.

[Tipover]

Thanks for the close up strut picture, all makes sense now.

I haven't been able to watch the video... I have not figured out how to download it yet from Putfile. Do you have to sign up as a Putfile member to download?

Kevin

[Geoff Dryer]

I am not sure that you can download the video. You can view the video without an account. You can also try
http://www.putfile.com/gdryer

[DavidN]

I clicked the link and it automatically started

[Tipover]

Probably not going to work with my dial-up connection.

Kevin

[renwick56]

How do you plan to mount your batteries? I will be using the following power system:

Rimfire 62-63-250kV
CC HV 110 ESC
12s2p A123 cells

Haven't figured out yet how to mount the batteries, such that I can get them secured and removed them when required thru the door opening.

Looking for ideas. Please let me know how you have/plan to accompish this.

Thanks,
Ren

I'm glad this thread is still alive!!!! I have all my gear but no time right now to build it.

I went the thrifty route. This is my gear:

TP5330-10t outrunner
Turnigy Sentilon 100amp esc
Turnigy 15amp bec
5 JR DS821 servos
5 GWS 111oz/inch servos.....don't know what I will use yet
A123 cells...either 10s2p or 12s2p

I hope everyone posts their progress.

[Geoff Dryer]

In case you missed it see the pictures of the battery tray near the bottom of page 3. I used two velcro straps. I glued thin foam to the bottom of the tray and I have grip tape (like sandpaper) on the bottom of the batteries. They will not slide very easily.

Getting the batteries in and out is OK through the door as long as the plane is on a table.

[renwick56]

Hi Geoff -

I did see the picture of your installation. My problem is that I have 2 packs that are about the size of your single pack, that I have to install.

I can build a tray up front in the tank area, but I see securing the pack with velcro as problematic.

That is why I was asking RMS, as he will have the same challenge that I have.

Ren

In case you missed it see the pictures of the battery tray near the bottom of page 3. I used two velcro straps. I glued thin foam to the bottom of the tray and I have grip tape (like sandpaper) on the bottom of the batteries. They will not slide very easily.

Getting the batteries in and out is OK through the door as long as the plane is on a table.

[karl k]

If you're using a123 packs and have trouble getting at your packs, just leave them in the plane!

Wire the plane so that you can charge the packs without removing them. I did this on my Husky and was able to fly for 10 minutes and charge in 20-25 minutes depending on how hard I flew the plane for the 10 minutes.

No real need to remove the packs with times like that.

Karl

[RMS]

Hi Guys,

Sorry to reply so late............. I haven't made my packs up yet for the SD. I started but then used some of them for another project. I have replacements though.

I was actually planning on leaving the batteries semi-permanently in the plane. I decided initially on making 6s sticks (12s2p) with balance taps and placing them on a sliding tray arrangement that would come out like a draw on the bottom of the filewall after removing the prop and cowl. Now I am thinking simple......drilling holes along the bottom of the firewall and sliding the 6s sticks through onto some fabricated supports. I can adjust how far into the fuse and how far out into the cowl compartment the need to be for CG adjusting. Fastening them with velcro straps or zip ties. Charging would be through the door or somewhere else. I have blinkies for balancing.

6s may be too long. I may have to make shorter sticks or make flat packs.

Back in the astro Cobalt brushed motor days, I sometimes made my nicad packs like sausage links and built them into the plane's structure. I can see doing this with A123s in some models.

I probably would balance the cells at the beginning of the day and end of the day.

If I have to remove the prop and cowl to get the batteries out once a week or a couple of times a month, it's okay with me. I still fly glow planes so I am used to regular maintenance on my aircraft LOL!!! I am not a safety nut but I like to check things regularly.

I think Karl is right. No need to stress over getting packs in and out to charge when using A123 batteries. Just leave them in there and charge in place.......but balance every half dozen charges.

I guess the biggest issue is balancing the model and I won't know until I get there......but I am not worried about it. If I have to add "dead" weight somewhere.....oh well. With that much wing area it won't be a problem. I'm not worried about ballistic verticals anyway........... I haven't ever seen a full size decathlon do that.

I am getting close to getting this plane ready.............I have been sidetracked............. I got the chopper bug and have been spending my free time flying/repairing the helicopters I bought. Choppers are such a money pit but the challenge to conquer the darn thing is like an addiction..............I could have bought another decathlon in what I have spent on heli repairs!!!!!

Did I mention that my Robinhood 80 is also getting an electric conversion?

[Geoff Dryer]

Managed three more flights on Decathlon.
Today I tested the differential that I programmed into the ailerons. This seemed to help but sometimes I still needed to use a little rudder to bring it around. It was really windy though.

I have noticed that it seems to climb in an aileron turn. Anybody have any ideas? I am thinking that it might be a little tail heavy still.

I did a landing in a severe cross wind while holding a lot of rudder. Great fun!

Members of the club commented on how scale it looks in the air.

[DavidN]

Are you flying at Burnaby?

[Gerry B]

Yes he is :). Geoff is one of my flying buddies. Unfortunately I wasn't able to make it out there today though.

[Geoff Dryer]

Yes David N I am a "hoods-Up" flyer.
I though a little bit more about my climbing turn and I am thinking that I may need more differential in the aileron throws. I will test this out next time.

[Tipover]

Managed three more flights on Decathlon.
Today I tested the differential that I programmed into the ailerons. This seemed to help but sometimes I still needed to use a little rudder to bring it around. It was really windy though.

I have noticed that it seems to climb in an aileron turn. Anybody have any ideas? I am thinking that it might be a little tail heavy still.

I did a landing in a severe cross wind while holding a lot of rudder. Great fun!

Members of the club commented on how scale it looks in the air.

The situation you describe is completely normal for the design of this plane. It’s basically a high wing thing. What you are experiencing is adverse yaw coupling. The full scale does the exact same thing. It’s completely normal to use aileron and rudder to make coordinated turns. You could set up a rudder to aileron mix if you're uncomfortable doing it manually.

[edit] After more thought I don't believe its only a high wing thing, but I think its more pronounced with a very high wing design. I think aileron differential will get rid of most of it on the best aerobatic designs, but I don't think it will completely cure the problem on a high wing. At any rate, I've never heard of a full scale plane making a coordinated turn with only differential aileron input.

Kevin

[Geoff Dryer]

Thanks for the information Kevin. I am getting used to coordinated turns and it turns much easier with the current level of differential aileron. I guess the bigger the plane the more scale it fies. I required no differential in my E-flite 25 Cub.

My Senior Telemaster was setup per the instructions to use differential and it does not require rudder. It of course is long way off from any full size plane in design.

[Tipover]

There’s definitely more yaw with larger aircraft, somewhat of a scale effect I guess. When you bank a plane with only ailerons, the lowered aileron half of the wing lifts more than the raised aileron side. The higher lift side (lowered aileron) creates more drag and yaws the fuselage opposite the bank angle. Once you initiate your turn with coordinated aileron and rudder, you can relax the aileron input and the plane should remain in the bank. The drag effect (yaw) should go away once the ailerons are relaxed.

Kevin

[karl k]

Very nice looking plane, Geoff.

I'm glad you're getting some flights in with the dodgy weather we have been having.

Karl

[Geoff Dryer]

Thanks for the pictures Karl.

[RMS]

Great photos! After seeing your model, I picked up that same tires. Gotta open up that front vent on the cowl though.......or paint it.

I'm going to take a day or two off from work next month so I can get this one ready.

[Geoff Dryer]

The tundra tires are great as they absorb much of the shock of the landing. These tires are very heavy at 6 oz each.

I was planning on opening up the vent but have not got around to it. I was also pondering mounting lights on the front. I found an LED flashlight (with multiple leds) that is about the right size. I think that it should be OK with the BEC voltage as the light runs on three 1.5 V batteries.

I am also looking for some lenses for lights on the wings. I was looking for a close up photo of the real thing to try and match it as close as possible.

[RMS]

Geoff,

I have been looking at the pictures on airliners.net for detail..........where are you looking?

Yes those tires do have some weight to them. I was shocked when I first picked them up.

Rick

[Geoff Dryer]

I have browsed airliners.net but have not found a closeup of the lights.

[RMS]

When I was into scale, I purchased some photo packs from Bob Banka at Scale Documentation. Not too long ago I purchased a small pack of Hazel Sigs Clipped wing Cub ........ another unfinished project. You might want to call him. He probably can sell you a few photos.

Rick

[renwick56]

I will be leaving the batteries in the airframe, however I still would like a good way to mount them securely, and be able to get them out when I need to. Here are pictures of the packs placed in the airframe. I need ideas!

Ren


If you're using a123 packs and have trouble getting at your packs, just leave them in the plane!

Wire the plane so that you can charge the packs without removing them. I did this on my Husky and was able to fly for 10 minutes and charge in 20-25 minutes depending on how hard I flew the plane for the 10 minutes.

No real need to remove the packs with times like that.

Karl

[Geoff Dryer]

I have seen several examples of a removable battery tray. The battery is strapped to the tray with velco then the battery and the tray slide into the fuse. The tray has hooks which connect with slots in the fuse. I will try and obtain a photo of this from one of the pilots who has done this.

[Gerry B]

Something like this Geoff?

http://www.rcgroups.com/forums/showpost.php?p=8775096&postcount=1358

[Geoff Dryer]

Thanks Gerry. I was about to email you about it. Something like Gerry did will work although some metal hooks might be better for heavier batteries.

[Geoff Dryer]

I finally went out and bought a digital fishing scale in order to test thrust.
I was not completely happy with the APC propeller on my Decathlon. At above 3/4 throttle it seemed to make more noise than thrust. I tried a Xoar electric wooden propeller. Below are the static testing results:

AXI 5320/18 on 6S

APC 18x12E 81A 1630W 8lb-12oz Thrust
Xoar 18x12 74A 1534W 10lb-5oz Thrust

In the air there is no comparison. The Xoar propeller is much quieter and the increase in power is very noticable. I suspect the problem with the APC propeller in this application is that there is too much flex.

I am really enjoying flying the Decathlon and I have been practicing scale acrobatics. I found a great video on YouTube showing a full size Decathlon in an airshow.

http://www.youtube.com/watch?v=EpBLUu6JuP0

[DavidN]

Well finally got my Decathalon. I expect it will be a while before it gets built, I have a line up and don't seem to be getting time. Help is on the way...retirement in 5 weeks.
DavidN

[Geoff Dryer]

Retirement, what a concept!

I continue to have fun flying my Decathlon. Last weekend I flew it at our club scale meet. A few pictures (including the Decathlon can be viewed at: http://www.hoods-up.com/forum/viewtopic.php?f=1&t=379

On my last landing of the day my wheel came off due to a failure of the axle. Luckily it just slumped over and no damage. On closer inspection the axle has an inner rod and an outer threaded tube. The threads separated from the rod allowing the nut to fall off. The other axle was also cracked. Consider the axles that come with this model suspect.

[zdsh13]

I was entertaining the idea of purchasing the RC Guys Decathlon but was thinking of a OS FF240 Peagasus glow, can someone tell me the distance from the firewall to the prop hub. Just want to ensure I have enough space before I make the purchase.

Thx

[Geoff Dryer]

There is play in the positioning of the cowling but on mine the distance from the firewall to the front of the cowling is 6.25 inches.