Re: COX .020 POWERED SPEEDSTER

rdw777 Fri Nov 08, 2024 9:28 am

Looks great TD Thumbs Up

….. I like the inverted engine…. Means business!!… Good luck on first flights!!

TD ABUSER Fri Nov 08, 2024 11:57 am

1/2A Nut wrote:LIFE batteries are out there it's a matter of where and when. I snagged enough while the getting was good before
vendor stock was not as obvious to find. Micro RC cars use them / micro solar lights use them dog / cat GPS.
Overseas folks are still keen to race micro cars.

6.6V 220mAh LiFe Receiver Pack - DYN1418
In stock
Brand: Dynamite
6.6V 220mAh LiFe Receiver Pack
https://www.hobbycorner.co.nz/product/6.6v-220mah-life-receiver-pack/dyn1418.aspx

https://www.amazon.com/dp/B0CR6H96GN/ref=sspa_dk_hqp_detail_aax_0?sp_csd=d2lkZ2V0TmFtZT1zcF9ocXBfc2hhcmVk&th=1
Product description
Brand: Dynamite
Description: 4.8V 220mAh 2/3AAANiMH 4C Flat: Micro SCT, Rally
SKU/Part #: DYNB0007
UPC: 605482588789

Thanks for those links.
I'd like to do business with the NZ store but first I want to see what the shipping will be.
I recently tried to get a NVA for a PAW .049 straight from England and the shipping was going to be $60. Mad

TD ABUSER Fri Nov 08, 2024 6:32 pm

rdw777 wrote:Looks great TD ….. I like the inverted engine…. Means business!!… Good luck on first flights!!

Thanks...!
The 5 flights went pretty well today but not perfect
The launches were all very easy but once the model got up to speed I didn't have enough aileron trim to cancel out a gradual roll to the right.
I adjusted the linkage but wasn't able to get it perfect
The roll rate WAS perfect for doing high speed laps...about 1 roll every 200 feet
Pitch control was hands off stable
With a constant wind of maybe 10 mph the model glided in with a pretty solid feel after it run out of gas IF it ran out of gas facing into the wind.
If it ran out while flying downwind//no matter how hard I tried to coordinate a nose down turn to get it facing upwind it would snap roll itself out of the sky and "helicopter spin" into a nice soft landing with no harm done except to my pride...... Mad

When this happens you might as well go to full lock on the stick to flatten out the spin and slow the plane down as much as possible.
5 flights total....3 good landings and 2 spins ...but all is well.
Tonight I'll get some higher pitch props ready to try [with custom machined adapters] and try to terrorize myself with more speed tomorrow.... Smile

If this plane could lose another ounce it would obviously be easier to land regardless of the weather, plus less total weight will make using higher pitch / less diameter props much more rewarding.
BTW I bought the smallest nitrile gloves I could find at HF and was able to make a lighter balloon tank. Even with the reduced size the tank was able to provide what I'm pretty sure was 2 minutes of run time.
If I don't butcher the prop mods ...I'll bet 70 mph speeds are in store.

1/2A Nut Fri Nov 08, 2024 9:48 pm

Thank you for sharing your flight observations,

Note best speed obtained with a 3.75x3P prop and TD .020 was 92mph with the Lil Speedy given its bulky design.
Final .020 speed test to 105 mph 3.5x3.5 / design was tested with a stock TD .049 to 118mph then retired as the
balsa fuselage was deemed to fragile to exceed higher speeds with a thumping snorting TD .049. and 4.4x5N

The Nano TD .020 started off with a cut HQ 4x4.5 tip cut to 3.7x4.5 (now a 4x4.5N would be a better choice)
The 3P prop would have flown faster with the Nano but deemed to low of a pitch given past progress.
N props with the leading edge left at full dia. is the best choice for discovery load testing
N and NN and N with tip cuts. Low weight lean TD .020 should be propped pitch loaded to 28-30k max.
Any more rpm then that wastes power for max .020 speed.

Thoughts on the flight observations:
When the tank is full the launch is steady, seems the empty tank pulls back the CG too far.
- seen this happen to my micro projects too. Superior tail airfoils help with control.

Based on swept wing and weight would concede to the nature of the beast to include
the choice in horizontal stab design and place the CG as shown.
- can hone back the CG for best stable glide thereafter.

Note my last change due to engine .051 mass and tail moment had a wider span for the horizontal stab.
The pink plane flies like a highly stable cadillac via the long tail moment was deemed a bit overkill.
I did want the same wing stability thus the wider span horizonal stab, paid off as the plane locks in.
Whips around in any wind speeds / directions with authority. Truly a good blueprint for all Cox engines.

Carbon custom props and fuselages would be a good next step. Proper hub dia. @ 4x5NN

COX .020 POWERED SPEEDSTER - Page 6 Imag9031

TD ABUSER Sat Nov 09, 2024 12:44 am

1/2A Nut wrote:Thank you for sharing your flight observations,

Thoughts on the flight observations:
When the tank is full the launch is steady, seems the empty tank pulls back the CG too far.
- seen this happen to my micro projects too. Superior tail airfoils help with control.

Based on swept wing and weight would concede to the nature of the beast to include
the choice in horizontal stab design and place the CG as shown.
- can hone back the CG for best stable glide thereafter.

A borderline CG is a possibility. I toyed with the idea of wrapping an inch worth of solder around the engine today just to see if the CG is to blame.
Tonight I balanced the whole plane side to side and found that it leans to the right [starboard wing panel is heavy]
I took some clear package tape and placed it on the port side wing tip,
It will be interesting to see the result of doing a little thing like that.

rdw777 Sat Nov 09, 2024 8:46 am

Thanks for sharing those flight experiences….I think when the ragged edge of top performance is being explored the “window” of tolerances gets much smaller….But rewarding when dialed in…. Appreciate what y’all have achieved Very Happy

….

1/2A Nut Sat Nov 09, 2024 10:25 am

Ok heavy wing on the right would add to the spinning, lead might be needed too.
That's part of the challenge, to sort them out to consistency and speed.

COX .020 POWERED SPEEDSTER - Page 6 Img_0714

NZ shipping likely over priced finding 220mah LiFe cells stateside may happen again.

I found these state side 220mah 3v 2/3A size used with cameras / rechargeable.
These may have very low weight for their size, looks suitable.

https://www.ebay.com/itm/314829518501?_trkparms=amclksrc%3DITM%26aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D276104%26meid%3D50409063daf94b1fbb191bb0261110d5%26pid%3D101506%26rk%3D10%26rkt%3D10%26sd%3D163766098593%26itm%3D314829518501%26pmt%3D0%26noa%3D1%26pg%3D4481478%26algv%3DDefaultOrganicWebWithV11WebTrimmedV3VisualRankerWithKnnV3AndUltBRecall%26brand%3DSureFire&_trksid=p4481478.c101506.m1851

balogh Sat Nov 09, 2024 10:36 am

Just bought 3 of these 500mAh LiPo batteries weighing 8.23 grams=0.29 oz each

COX .020 POWERED SPEEDSTER - Page 6 17311710

1/2A Nut Sat Nov 09, 2024 1:58 pm

Ebay USA

I now see why the 220 mah went away: 550 /650/900 6.4v LiFePO4 is the current RC car micro trend
All in the same size cell progression in mah increases the key search is: 3.2v / LiFePO4 not 3.3v LiFe

Example in AAA
3.2 Volt LiFePO4 10440 (AAA) Button Top Battery (300 mAh)

Appears 220 has progressed to 280mah micro cars in the US has improved past my old search specs lol.

Spotted this chart with weights in grams 3.2v

COX .020 POWERED SPEEDSTER - Page 6 S-l16047

Another key word is "Polymer" if you want bagged cells:

COX .020 POWERED SPEEDSTER - Page 6 3_2v_210

3v Low mah USB charge cords USA
https://www.ebay.com/itm/267038121039?_trkparms=amclksrc%3DITM%26aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D275254%2C276199%2C276104%26meid%3De9219a59ca354b4e80499eda8be1526f%26pid%3D101875%26rk%3D1%26rkt%3D4%26sd%3D315211356937%26itm%3D267038121039%26pmt%3D1%26noa%3D0%26pg%3D4481478%26algv%3DSimVIDwebV3WithCPCExpansionEmbeddingSearchQueryRecall%26brand%3DUnbranded&_trksid=p4481478.c101875.m1851&itmprp=cksum%3A267038121039e9219a59ca354b4e80499eda8be1526f%7Cenc%3AAQAJAAABIEK7FTfzsGw0VauxYyX1IOHjsuXJ1NPjVWebvOca%252BJbVzh3VqcrGnLFKHjKk2M42BtfNs8bK1jFneKBZqmubi3LoF9ino0LoTI5PT7k5yPChvi%252FuSvv7Bq01fv%252FJgtwWF8Ze5Eq9rvPLJX%252FTT1R2bNGgxWwXj%252BGbaPSt0S11CYPMD8O2tBZVJ9ikZ499Rv2RAuzbwa7GB6fA832O1n8q3D1MMf56WQhiKUbxUSyTOcAdtKEwyqxhmoY0OcJOwtDPR7PZN%252BEY8ABULGq0g65jjUPvwl3pCGgm5k2SAIf9ynsWzfWypMuEvqhizUCcJnb2O6VsmwFyhKcWXc%252BlUcCbDeNuemJ%252F2N3623Tb6ceuFccNK1vDh5zksTnHUYoOn0sfVw%253D%253D%7Campid%3APL_CLK%7Cclp%3A4481478&itmmeta=01JC980K946BJFF6YBN18BS2N8

AAA button cell holders

COX .020 POWERED SPEEDSTER - Page 6 S-l16048

The mystery has been solved!

Small Cox Logo

TD ABUSER Sat Nov 09, 2024 2:49 pm

1/2A Nut wrote:Ok heavy wing on the right would add to the spinning, lead might be needed too.
That's part of the challenge, to sort them out to consistency and speed.

I found these state side 220mah 3v 2/3A size used with cameras / rechargeable.
These may have very low weight for their size, looks suitable.

https://www.ebay.com/itm/314829518501?_trkparms=amclksrc%3DITM%26aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D276104%26meid%3D50409063daf94b1fbb191bb0261110d5%26pid%3D101506%26rk%3D10%26rkt%3D10%26sd%3D163766098593%26itm%3D314829518501%26pmt%3D0%26noa%3D1%26pg%3D4481478%26algv%3DDefaultOrganicWebWithV11WebTrimmedV3VisualRankerWithKnnV3AndUltBRecall%26brand%3DSureFire&_trksid=p4481478.c101506.m1851

Way back when the .061 AME first came out [26,000 with a 5 x 3 prop] and the VA .049 I was inspired to build the lightest possible plane I could for those engines. Part of the problem was finding a lighter battery.
We had no internet...just hobby shops and hardware stores for our "search results".
I think a 4 cell, AAA pack was as light as you could go.....but I came across a 6V camera battery [probably at K mart] about the size of a piece Bazooka Joe bubble gum and that was enough power for quite a few flights until the battery was pooped out. Kind of expensive, but worth the thrill of seeing a 1/2A RC plane capable of unlimited vertical.
This was back when getting a 2 channel RC plane under 16 ounces required expensive Cannon RX / Servo system and your sportiest choice for a kit might have been a ACE RC GLH.
I think this little delta was RTF at 12 ounces or so and capable of drilling long vertical holes in the sky.
The biggest break through in "micro" servos were the very expensive and very unreliable Futaba S133s.
They cost something like $33 each...!
Here we are 35 years later and I would still consider using one of those 6v camera batteries if that was my only choice for going tiny.

COX .020 POWERED SPEEDSTER - Page 6 Img_0742

COX .020 POWERED SPEEDSTER - Page 6 Img_0743

1/2A Nut Sat Nov 09, 2024 4:25 pm

Could you imagine how fast that delta would have been with an APC 4.4x5.5N
If my piped TD gets 149.7 prop pitch speed and 143 mph down wind likely
127-130 mph would have been possible down wind with that 12oz AME Delta.

I had a 4ch Futaba Attack with S133's and a sleeved .051 do taxi out to acro
with a scratch built low wing, then it was nicads using 2/3rd 270 mah AA phone
batteries 1989, was considered best possible rig of the day with a Cox 5x4
3 flights a pop with onsite recharging for 2 extra flights at the club field using
the stock 120v Futaba 4 cell trickle charger.

Here is the Sanyo N-270AA-ST NiCd - Nickel Cadmium Battery 2/3AA TB 270mA
Capacity has improved with nicad chem. 2/3 AA 350 and 400mah today.

COX .020 POWERED SPEEDSTER - Page 6 S-l16049

COX .020 POWERED SPEEDSTER - Page 6 Bgn40010

gkamysz Sat Nov 09, 2024 6:31 pm

Those CR123 size LIFE are 16-18g each. Spektrum has a 2s300 at 24g.

https://www.towerhobbies.com/product/6.6v-300mah-2s-life-receiver-battery-universal-receiver/SPMB300LFRX.html

I flew F5D electric pylon with a 4 cell 50mAh pack. It always took the same amount to top off regardless of how many time I flew it. Granted, flights were 3 minutes.

TD ABUSER Sat Nov 09, 2024 6:50 pm

balogh wrote:Just bought 3 of these 500mAh LiPo batteries weighing 8.23 grams=0.29 oz each

Thanks for the information...!
The 3.7 to 5v converters and the 3.7v LIPO showed up just now.
Will the converter drain the battery if the 3.7volt input wiring is left connected [if no on / off switch is used]...?
I would like to just have a female plug wired to the circuit card that the battery plugs into.

TD ABUSER Sat Nov 09, 2024 6:58 pm

1/2A Nut wrote:Could you imagine how fast that delta would have been with an APC 4.4x5.5N
If my piped TD gets 149.7 prop pitch speed and 143 mph down wind likely
127-130 mph would have been possible down wind with that 12oz AME Delta.

I had a 4ch Futaba Attack with S133's and a sleeved .051 do taxi out to acro
with a scratch built low wing, then it was nicads using 2/3rd 270 mah AA phone
batteries 1989, was considered best possible rig of the day with a Cox 5x4
3 flights a pop with onsite recharging for 2 extra flights at the club field using
the stock 120v Futaba 4 cell trickle charger.

Here is the Sanyo N-270AA-ST NiCd - Nickel Cadmium Battery 2/3AA TB 270mA
Capacity has improved with nicad chem. 2/3 AA 350 and 400mah today.

I needed to make that delta VERY FAT to house the fat little RX and the fat little servos and the fat little bladder compartment. Smile

Fat little wings can go surprisingly fast,,,but I think that phenomenon is more evident with much larger flying things.
[The ME 163 is basically a fat little football with wings and there are some .90 sized models that are amazing].
I remember the 270 ma pack being the standard of rechargeable tininess back in the day...so it's great to see it's ampacity shoot up to almost what I used to spend all day flying 40 sized stuff with [500 mah AA packs],

TD ABUSER Sat Nov 09, 2024 7:12 pm

gkamysz wrote:Those CR123 size LIFE are 16-18g each. Spektrum has a 2s300 at 24g.

https://www.towerhobbies.com/product/6.6v-300mah-2s-life-receiver-battery-universal-receiver/SPMB300LFRX.html

I flew F5D electric pylon with a 4 cell 50mAh pack. It always took the same amount to top off regardless of how many time I flew it. Granted, flights were 3 minutes.

and so the overnight charge rate was 5ma
I seem to recall ruining a pack or 2 of these cells from failing to take them off slow charge in time...?

balogh Sat Nov 09, 2024 11:17 pm

TD ABUSER wrote:
balogh wrote:Just bought 3 of these 500mAh LiPo batteries weighing 8.23 grams=0.29 oz each

Thanks for the information...!
The 3.7 to 5v converters and the 3.7v LIPO showed up just now.
Will the converter drain the battery if the 3.7volt input wiring is left connected [if no on / off switch is used]...?
I would like to just have a female plug wired to the circuit card that the battery plugs into.

The converter drains very low amount if disconnected from the RX, the battery voltage drops less than 0.1V in 2 months, I decided to use the Zepsus feather weight magnet switch between the converter output and the RX to avoid the need for manual disconnection after each flying session. On the input end I soldered the battery direct to the adaptor with the male battery connector wired also, which is accessible outside the plane for charging.

COX .020 POWERED SPEEDSTER - Page 6 17312110

TD ABUSER Sun Nov 10, 2024 12:27 am

[quote="balogh"][quote="TD ABUSER"]

balogh wrote:Just bought 3 of these 500mAh LiPo batteries weighing 8.23 grams=0.29 oz each

The converter drains very low amount if disconnected from the RX, the battery voltage drops less than 0.1V in 2 weeks, I decided to use the Zepsus feather weight magnet switch between the converter output and the RX to avoid the need for manual disconnection after each flying session. On the input end I soldered the battery direct to the adaptor with the male battery connector wired also, which is accessible outside the plane for charging.
]

Thanks so much for the information..!
I assumed you use the switch for a very good reason.
I'm just trying keep the amount of "spaghetti" inside the plane to a bare minimum..it already looks like a "rat's nest" of wires sharing space with the aileron linkage.

balogh Sun Nov 10, 2024 12:38 am

Yes I see your point..albeit only a COX TeeDee 010 powered 2-channel micro racer, my Shoestring belly is also full of guts that I would not call what electricians call a marshalling box.

COX .020 POWERED SPEEDSTER - Page 6 17312210

The real estate inside is also robbed partially by the tare volume of small plastic pouches I placed the power supply and RX units in, in hopes castor will not find its way to them...a naive expectation, castor is a more efficient explorer than Columbus and Magellan combined..

(Never mind the geasy looks, this beast has already many hours of castor-drenched airtime on its clock, with the fantastic COX TeeDee 010 in as-new condition too)

TD ABUSER Sun Nov 10, 2024 2:09 am

balogh wrote:Yes I see your point..albeit only a COX TeeDee 010 powered 2-channel micro racer, my Shoestring belly is also full of guts that I would not call what electricians call a marshalling box.

The real estate inside is also robbed partially by the tare volume of small plastic pouches I placed the power supply and RX units in, in hopes castor will not find its way to them...a naive expectation, castor is a more efficient explorer than Columbus and Magellan combined..

(Never mind the geasy looks, this beast has already many hours of castor-drenched airtime on its clock, with the fantastic COX TeeDee 010 in as-new condition too)

What you have inside your plane looks like a very well organized mess.... Laughing

getback Sun Nov 10, 2024 6:41 am

Andres are you only running alerions and elevator ?
The Delta was Fast wild looking thing Very Happy

balogh Sun Nov 10, 2024 8:09 am

Hi Eric, yes, the kit was made to allow the use of rudder as well, but my experience with ailerons+elevator only is positive and I left the rudder fixed with no control. Hence I saved some space and weight on account of the servo, pushrod and other accessories for rudder control all omitted..the plane - Shoestring Micro Racer - flies very well on these 2 channels only.

getback Sun Nov 10, 2024 8:38 am

Thanks , I know when I was fling RC there was a thing called slipping or skidding ? , it was where the plan with out using both together would cause this effect and would go wide in the corners . This was on 40 size planes though . Here is a young man doing it Kind of >

TD ABUSER Sun Nov 10, 2024 9:29 am

getback wrote:Thanks , I know when I was fling RC there was a thing called slipping or skidding ? , it was where the plan with out using both together would cause this effect and would go wide in the corners . This was on 40 size planes though . Here is a young man doing it Kind of >

That was a great performing plane...!

Years ago a guy posted a video at the 1/2A forum at RCU of his 4 channel .074 powered 3D profile plane. He could make it do every trick in the book including landings on picnic tables. When it comes to doing the FULL 3D ROUTINE the rudder is every bit as important as any other control.

gkamysz Sun Nov 10, 2024 11:51 am

TD ABUSER wrote:
gkamysz wrote:I flew F5D electric pylon with a 4 cell 50mAh pack. It always took the same amount to top off regardless of how many time I flew it. Granted, flights were 3 minutes.

and so the overnight charge rate was 5ma
I seem to recall ruining a pack or 2 of these cells from failing to take them off slow charge in time...?

This was around 1999 or 2000 and I was using Orbit Microlader and Astro 112D chargers. I always peak charged the 50mAh probably at 4C or 200 mA. Never any trouble, just recently threw it away, I should have tested it.

What we have available now is incredible. Though, I have doubts about servo quality. I have little experience with more recent tiny servos. F3K uses similar gear and many run single cell LiPo. https://flightpoint.co/best-dlg-servo/

TD ABUSER Sun Nov 10, 2024 3:07 pm

gkamysz wrote:
TD ABUSER wrote:
gkamysz wrote:I flew F5D electric pylon with a 4 cell 50mAh pack. It always took the same amount to top off regardless of how many time I flew it. Granted, flights were 3 minutes.

and so the overnight charge rate was 5ma
I seem to recall ruining a pack or 2 of these cells from failing to take them off slow charge in time...?

This was around 1999 or 2000 and I was using Orbit Microlader and Astro 112D chargers. I always peak charged the 50mAh probably at 4C or 200 mA. Never any trouble, just recently threw it away, I should have tested it.

What we have available now is incredible. Though, I have doubts about servo quality. I have little experience with more recent tiny servos. F3K uses similar gear and many run single cell LiPo. https://flightpoint.co/best-dlg-servo/

Greg thanks for the 50 miliamps worth of endorsement.... Laughing

I think when it comes to servos it was the Hitek servos with the carbonite gears that revolutionized micro servo durability. I've wondered if the Cheap Chinese Servos [CCS] use similar gears because I haven't failed any 9 gram or 5 gram servos yet.

So those 3.7 volt servos are GREAT INTEL I wont hesitate to try them. Thanks..!

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