Chilli Breeze & Chilli Wind plans (was RCME June 1994)

[Nigel R]

Chilli Karma looks to be quite similar to the Wind, but -

 

slightly less sweep on the wing?

with a slightly deeper fuselage?

stretched a little, to put rudder entirely behind the tailplane?

[kc]

I reckon we would all like to see a new aerobatic plan in RCME!   The Karma perhaps?...........

From my point of view a 53 inch span model would be ideal and it would be very nice to see an electric version.  .

[Delks]

2 hours ago, Jonathan M said:

Hi Mike

Really appreciate these extra photos and input.

There are clear advantages in mounting the U/C on the fuselage:  would make my Breeze less 'tippy' on our sometimes bumpy patch, and would save having to beef up the foam wing.  There's certainly enough room in the fuselage for two modern micro servos for the ailerons, but modern wing-mounting would also be an option.

Cheers

Jon

Hi Jon - my preference would be to put the servos in the wing - plenty of good spec mini/micro servos available that would do an excellent job for you.

Cheers

Mike  

[Delks]

7 hours ago, kc said:

I reckon we would all like to see a new aerobatic plan in RCME!   The Karma perhaps?...........

From my point of view a 53 inch span model would be ideal and it would be very nice to see an electric version.  .

Hi KC

Interesting that your preference would be for a 53" span model - do you also have an electric set up in mind? Interestingly this size would correspond to the average "40 size" aerobat from the 1970's  (Crescent Bullet, Mini Atlas etc)  could we consider designs using the popular 3s 2200 size battery as "20 size" models (MM Starlet, Zippy etc). Over the past year I have been messing about with 450 size helis so I think you can guess what is also in my mind.......................... 

Cheers

Mike

[Jeffrey Cottrell 2]

Hi Guys

Regarding undercarriages, there is always a plan B, or is it C...D...

Here

Jeff

 

[kc]

53 inch span is a reasonable size to see, yet still goes in the car easily.   Also gives reasonable wing area.   A lot more practical for me than 48 inch.    I have an Avicraft Moronic which has flown well on a Turnigy 3536/9 with a 4S3000 giving 500 watts on an 11 by 5.5 prop.   A cheap setup which only needs a 40 amp ESC.   52 inch span and about 4 pounds weight.   So far it has done 1945 flights each of about 6 minutes full throttle all on the original motor but on it's second ESC.   So I would use that for any similar size model and build to 4 pounds if possible.  Not a lot dearer than the 3S2200 but a lot more fun.  I don't consider a 3S2200 suitable for an aerobatic model of 53 inch span.

 

It seems to me that electric is the thing now but there are some who will only use i.c.    It would be nice if new plans showed an alternative front end for electric with top hatch for Lipo and the motor bulkhead a bit further forward than the i.c version.   Being able to just get straight on and build to the plan rather than adapt it for electric before starting the build would be so much nicer.   I hate using lead to balance the model so I like the Lipo to be able to go well forward if needed, hence the forward positioning of the bulkhead suits my purpose.

[Nigel R]

52", or around 500 sq in wing, is "compact 40" size to me... 4s3000 would make for a short flight at this size. 4s4000 - 4500 feels better for an 8 to 10 minute flight. Something like Diamond https://outerzone.co.uk/plan_details.asp?ID=9344.

 

Chill Karma looks like a "big 40"... 575 sq in? 4s4000 minimum, 5000 would be better. Possibly 5 cell at this point.

 

3s2000 is more like a 15 equivalent for me. 3s3000 works better in the old "20 class" size, IRO 350 sq in or 40" such as Mach 20 https://outerzone.co.uk/plan_details.asp?ID=8870

 

3s3000 is definitely my favourite electric size. Anything larger I prefer noisy and oily. Motors are part of the fun! Others may disagree?

 

Some folk like to fit tiny lipos and have very short flights.

 

If you do a plan for anything 40 size and under it would want to be electric first with a glow option.

[Delks]

 

Hi KC

Many thanks for the interesting reply - just the input I was looking for! A good friend has built several Chilli Breeze (48" span) models for electric power using 4s set ups and was pleased with the performance provided. I was not very clear in my last post but I was in fact thinking of the 3s 2200 route for a "pocket size" aerobat of around 42" span. Over the past year I have been converting a Veron Strutter that I am building (originally finished for an OS.25) to electric power using an Airmax 3536 motor and (yes - you've guessed) a 3s 2200 battery. I am impressed with the power it produces  and it is also a compact, lightweight set up but not quite enough (in my opinion) for a 53" span  model. Whilst electric power  seems to be today's "norm" I do appreciate that there are still i.c. aficionados out there so I would definitely be considering an ic/electric design. I would like  to aim for both versions to be built without the need for a removeable cowl so am considering a slightly different-than-norm method of mounting the electric motor.

 

I also hate having to use nose weight to balance a model so tend to err on the side of caution and, as there was so little flexiblity re gear placement in an i.c.model, small changes to the c of g were accomplished by using small weights at the tail end. This is not a big problem for an electric model as the lipo can be moved to achieve the desired result - as you mentioned. 

 

By the way - well done for keeping the Moronic in one piece for 1945 flights (and still counting!) - very impressive indeed.

 

Cheers

 

Mike

 

 

 

 

 

 

[Delks]

1 hour ago, Nigel R said:

52", or around 500 sq in wing, is "compact 40" size to me... 4s3000 would make for a short flight at this size. 4s4000 - 4500 feels better for an 8 to 10 minute flight. Something like Diamond https://outerzone.co.uk/plan_details.asp?ID=9344.

 

Chill Karma looks like a "big 40"... 575 sq in? 4s4000 minimum, 5000 would be better. Possibly 5 cell at this point.

 

3s2000 is more like a 15 equivalent for me. 3s3000 works better in the old "20 class" size, IRO 350 sq in or 40" such as Mach 20 https://outerzone.co.uk/plan_details.asp?ID=8870

 

3s3000 is definitely my favourite electric size. Anything larger I prefer noisy and oily. Motors are part of the fun! Others may disagree?

 

Some folk like to fit tiny lipos and have very short flights.

 

If you do a plan for anything 40 size and under it would want to be electric first with a glow option.

Great to read your reply. I don't think I made  myself clear - I was thinking about the 3s2200 for a "pocket size" design (around 42" span) but would consider a 4s set up to be the minimum for a standard Chilli Breeze or 53" span Chilli Karma. I have had a lot of fun with smaller electric stuff -  foamies and 450 helis -  which would not have been possible with ic but, like yourself, I do feel that for anything larger the noble i.c. engine still has a lot going for it.   

[Nigel R]

Hi Mike

 

I was just thinking aloud really, in part responding to kc's post as well as yours.

 

Quote

a slightly different-than-norm method of mounting the electric motor.

 

On my Wind (all my dad's work this one) the motor (3648 size) goes through the spinner ring. No access holes anywhere. It is just plain screwed to the firewall with self tappers. There is a small air scoop underneath.

 

Obviously the spinner has to be a fair size for that arrangement to work.

 

The ESC is tucked in with the lipo. The firewall was moved forward about an inch.

 

It's a tidy end result and also cuts down on covering effort. I wish I'd thought of it!

 

[Delks]

That is an excellent solution if the components match - your dad had the right idea.

 

Cheers

 

Mike 

[kc]

Nigel is right that a 4S4500 would give a longer flight time but of course the extra weight would reduce the vertical performance which in my Moronic is very good.   6 minutes of full performance and a couple of extra minutes stooging around is enough for me.    However any model could be made to take either Lipo size and give both options.

The Moronic I have is much modified in that the OS46AX was removed and the nose extended to put the motor bulkhead 5.5 inches forward.  This was not calculated but found by experiment- the motor and Lipo were lashed up on a bit of ply and moved forward until the CG was correct.   Then a liteply structure ( open top box really ) was constructed which contained the Lipo and fitted onto the original firewall.   The original motor mount captive nuts needed to be moved outwards a bit to enable a hole in the firewall to take the Lipo.    On measuring the electric version it is 7.25 inches prop driver to original firewall.   I think the OS 46AX would be 3 inches less.    So thats my point a .46 with tank & mount weighs about the same as a 3536 with 4S3000 but the weight in the OS is all at the front so electric needs the Lipo to go further forward to maintain same CG.

I  should note that the kv of my motor is 910kv and this  suits 4S but a change to a 3S would probably suit a higher kv of perhaps 1100kv.

 

Thank's for the comment about the number of flights  - gravity willing I should have reached my target of 2000 by now but for the Lockdown!

 

[kc]

One of my theories is that a ply doubler is needed on a model to keep it straight & make it rebuildable in the case of damage but it doesn't need to be as extensive on an electric model as i.c.  as there is less vibration.    The Chilli Wind ply doubler is a lot less than some models but maybe it could be reduced in height a bit for electric.   As long as it connects the firewall, u/c mount, F2 and extends just behind the wing it might be enough especially as a tray to hold the lipo is needed which will add some strength too.   Reducing the ply would also reduce the amount of heavy rubbery contact glue needed too.  

 

[Delks]

I don't believe that reducing the size of what is already a small ply doubler will have any measurable effect on the performance of the Chilli Breeze/Wind. There are several other weight saving measures that would be worth looking at:

1) Use a built up wing.

2) Lightweight c/f undercarriage (and wheels) attached to the fuz instead of the wing.

3) Substitute the elevator push rod for a Sullivan Golden Rod type of connection.

4) The model was designed to be capable of accommodating standard servos such as the Futaba 3001 (weight 45gms) because this is what the average sport flyer used at the time- we are lucky now to have a huge choice of reasonably priced mini/micro servos with useful performance figures. Receivers have also shrunk in size.

5) Making some lightening holes in the doublers will of course be another solution but, out of interest, weigh the material that you have removed...............

 

 

 

 

 

 

 

 

 

 

 

[Delks]

On 19/02/2021 at 13:18, kc said:

One of my theories is that a ply doubler is needed on a model to keep it straight & make it rebuildable in the case of damage but it doesn't need to be as extensive on an electric model as i.c.  as there is less vibration.    The Chilli Wind ply doubler is a lot less than some models but maybe it could be reduced in height a bit for electric.   As long as it connects the firewall, u/c mount, F2 and extends just behind the wing it might be enough especially as a tray to hold the lipo is needed which will add some strength too.   Reducing the ply would also reduce the amount of heavy rubbery contact glue needed too.  

 

Hi KC - Many thanks again for the feedback in the pm's - much appreciated. A few more thoughts on electric powered Chill Breeze/Wind construction. On the subject of ply doublers the big question is: are they really necessary at all? With a view to simplifying construction even further why not dispense with the ply doubler completely and extend the 3/32" (or even 1/8") balsa  wing seat  reinforcement from the  front F1 to  to the rear extent of the ply doubler as shown on the plan- total length about 460mm - and this would also provide a good support for mounting the battery tray. It will also do away with the need for the use of "heavy rubbery contact glue" which would an extra bonus!!! A little bit of extra reinforcement around the captive nut plate would be a good idea. Assuming we now have wing-mounted aileron servos why not put the elevator and rudder servos in the tail end. And finally, has anyone built a "one piece" Chilli breeze with a glued-on wing yet? I have built a one piece model of this size in the past and it was very practical - although I must admit that covering was a bit of a wrestling match. 

 

The biggest problem at the moment is the lack of balsa supplies but the good news from SLEC and the Balsa Cabin is that new stocks will be arriving in the near future so let's keep our fingers crossed!  

Cheers

Mike

 

   

[Nigel R]

Mike, couple of thoughts

 

Electric in this sort of size, you can drop a fair bit of structure, e.g. go down to 3/32" thickness sides and even 1/16" top sheeting if you are careful with handling (although I find it is a bit too thin, prone to cracks, obviously I'm a bit of a klutz!). You could lose the spruce longerons, or go to balsa if anything is even needed. Diagonal grain 1/16" med/hard balsa works as a doubler and is lighter than thin birch ply. Or, use a narrow strip ply doubler, running along the lower edge of the fuz only, wide enough to clear the wing cutout by a 1/2"? Or as you say, use the balsa wing seat doubler and extend it forward to FW and back a little to take the job of the ply doubler. All could work.

 

Keeping the tail end light is the prime thing though. You might get away with an open structure? Servos at the tail end serve to make the tail heavier. Hence my preference in this size is still for servos (25g or thereabouts, say HS225) in the wing area with closed loop (light), or the light red Sullivan snakes (also very light). A bolt on wing also makes an excellent access hatch. If you glue the wing on you still need to get to the RX and whatnot inside which probably means as much effort making a hatch somewhere else.

 

I'd be interested to see whether a carbon U/C saves that much over two wire torque rod type U/C legs. Maybe more mileage in using lightweight sponge wheels vs the usual heavier IC friendly type. Off the wall idea - main monowheel, tip skids, plus tail skid?

[kc]

I think we are all hoping Mike is designing a new model with intentions of publishing the design - we really need up to date designs!

In that case I suggest a published design should allow for the fact that some of us fly from rough grass strips so a tough u/c and ply doubler may be important.  The doubler should be shown and could always be left off by those who want.

A torque rod u/c works well but not everyone likes bending piano wire, so again the option of a carbon u/c should be shown.  Fuselage mounted u/c is better in my opinion and it's so much easier to store and transport a model without u/c on the wings.

 

A while ago in the Ballerina mass build thread one person decided a built up tailplane would be lighter and I doubted that and said there was not much advantage over solid balsa well chosen.   So it ended up a challenge - i built a solid one, the other man built up and we both weighed them.  I lost but the difference was so slight it was acknowledged that it was not worth while building up from strip.  So I feel a solid tail is more attractive to builders.   Less vulnerable to damage in transport too.

 

Nowadays there are lots of experienced pilots who have little experience of building.   New designs should allow for that.

My pet hate is plans that are CAD drawn with formers etc that are so fiddly they can only really be lasercut and are not at all easy by hand cutting methods.    Several designers seem to relish the idea of complex interlocking parts and use them everywhere!   The good old straight former designs appeal to me much more.   Am I alone in this?

 

[Delks]

11 hours ago, Nigel R said:

Mike, couple of thoughts

 

Electric in this sort of size, you can drop a fair bit of structure, e.g. go down to 3/32" thickness sides and even 1/16" top sheeting if you are careful with handling (although I find it is a bit too thin, prone to cracks, obviously I'm a bit of a klutz!). You could lose the spruce longerons, or go to balsa if anything is even needed. Diagonal grain 1/16" med/hard balsa works as a doubler and is lighter than thin birch ply. Or, use a narrow strip ply doubler, running along the lower edge of the fuz only, wide enough to clear the wing cutout by a 1/2"? Or as you say, use the balsa wing seat doubler and extend it forward to FW and back a little to take the job of the ply doubler. All could work.

 

Keeping the tail end light is the prime thing though. You might get away with an open structure? Servos at the tail end serve to make the tail heavier. Hence my preference in this size is still for servos (25g or thereabouts, say HS225) in the wing area with closed loop (light), or the light red Sullivan snakes (also very light). A bolt on wing also makes an excellent access hatch. If you glue the wing on you still need to get to the RX and whatnot inside which probably means as much effort making a hatch somewhere else.

 

I'd be interested to see whether a carbon U/C saves that much over two wire torque rod type U/C legs. Maybe more mileage in using lightweight sponge wheels vs the usual heavier IC friendly type. Off the wall idea - main monowheel, tip skids, plus tail skid?

Hi Nigel - quite agree with the points you make re weight saving. Don't forget that these designs were for i.c. power and I did not feel that they were overbuilt. The Breeze has 3/32" sides + 1/16" top and bottom sheeting whilst the Wind had 1/8"sides and 3/32" sheeting. Re a built up versus sheet tail - I have used both and found, like KC, that there was very little difference in weight. The choice of spruce or balsa longerons was suggested on the plan but I think most builders would have chosen  balsa. I agree that there is the potential for introducing a c of g  problem by mounting servos in the tail but it does seem to be quite a popular choice these days - I suppose people compensate by moving the battery? The one-piece model was not a serious suggestion but the access to the interior in this case would via a hatch in the top of the fuz so it would be quite a practical proposition - especially if you like wrestling! I remember the u/c on the Karma being very light and the Dave Brown wheels weighed very little too .

Good to hear your thoughts.

Cheers

Mike 

 

 

 

  

 

 

 

i

 

[Delks]

I was clearing out a some old bits and pieces today and I came across these photos which were sent to me by an enthusiast way back in the mid '90's - the note on the back of the top photo read:

" Me holding the Chilli Breeze which I built from  the RCM&E plan. Power is Magnum C.P. .25 and other club members  cannot believe  the performance on the motor, weight is 3lb 3oz (less fuel)."

The model has a built up wing and an engine on the lower end of the range so I see no problem with a nice little 4s set up! 

 

[Jonathan M]

There's virtue in adding lightness!

[Delks]

Hi Jonathan - Couldn't agree more but how much "added lightness" are we talking about?  I have just weighed a 36" x 4" sheet of 1/16" "medium" balsa- total weight 0.9oz and a sheet of similar 3/32" weighed 1.2oz........

 

[kc]

 

When I was electrifying a model that had an OS.46 AX  I made up a crude balance that you can see in the photos - it pivots on two pointed screws onto the orange Formica surface.   So OS 46 on one side and the Turnigy 3536 and 4S3000 on the other.   Thats the balance changed by the 4.8 nicad pack.   Note that that is a .46 not a .25 that equals the 4S3000 ( and not even a 4S5000 )

It's such a crude setup but easily proves the point.

Edited February 27, 2021 by kc

[kc]

To explain my photos  - the crude method shown illustrates that an OS46AX without silencer is close to the weight of a 3548 ( not 3536 ) with 4S 3000. With nicad it's heavier.   The plank its mounted on has the centreline to edge/propdriver the same distance as the CG to prop driver on the particular design being considered.

Actually the OS46AX with silencer weighs 18.75 oz and a Turnigy 3548/6 with 4S3000 weighs 18.5 ozs so thats very close.   But of course the weight of the OS is all up the front while the Lipo weight 11.75oz goes a lot further back.    The setup shown allows one to see that when the Lipo is right up close to the motor it just balances but move the Lipo even a bit further back it won't.  What this means is that methods of mounting electric motors on standoffs or an a solid box will prevent the Lipo going right up close to the motor and need lots of lead instead.   So I am very much of the opinion that electric versions need the firewall mounted further forward.   Mounting on a hollow box that allows the lipo partly inside might work though.  A bigger Lipo would work too but increase overall weight.

All very obvious but it is surprisng how being able to juggle around with the items reveals the problem or solution.

Older aerobatic designs and some very modern  were deep at the front unlike the Chilli's and I wonder whether such design might even allow the Lipo to actually go beneath the motor.

 

[Nigel R]

Mike my irvine 36 breeze was 3-1/2lb dry. Cannot recall deviating from plan. Film covered, built up.

Micro rx, micro wing servos, mini in fuse, and a 2/3 aa pack. I think.

Careful wood choice!

 

At the time i was also flying a 4' fun fly with a magnum gp 25, standard radio 5 servos, 3-1/4 dry. Litespan covered i believe. Again weight dictated by wood choice. 

[kc]

Since the title was changed nobody has posted anything more!   I expected that the change of title to show what the thread was actually about would bring in more people.........