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Converting PZ Spitfire to brushless

Old 11-11-2008, 07:54 PM
  #426  
LectricPlane
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On something this size would they not add a bit much weight and turn it into a flying tobogan?
:-)
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Old 11-11-2008, 08:08 PM
  #427  
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With the amount of foam removed to install them, it's not much added weight. And this is for a brushless upgraded plane and to a 4 CH radio. It will not work on an out of the box Spitfire.
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Old 11-11-2008, 08:46 PM
  #428  
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Originally Posted by SpitfireTrembly View Post
Yeah. You'd have to have a parking lot or the like to let it land and coast to a stop. But that's not too hard to find. It's just a project i am trying, because i hate belly landing my planes.

I think over at RCG there is a thread on the 'Stang where GlacierGirl put both a rudder and retracts on the bird, and it turned out good.

GRU
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Old 11-11-2008, 09:35 PM
  #429  
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I thought about also adding rudder to this project, but i'd have to get a 5-6 CH radio for that to work. I had a 4 Ch radio on hand and figured i'd give the retract project a try in case anybody else wanted to try it.
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Old 11-12-2008, 02:43 AM
  #430  
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Originally Posted by SpitfireTrembly View Post
I thought about also adding rudder to this project, but i'd have to get a 5-6 CH radio for that to work. I had a 4 Ch radio on hand and figured i'd give the retract project a try in case anybody else wanted to try it.

Well I'm looking forward to seeing how it works out. I just bought a Parkzone T-28 trojan and I'm looking to tackle retracts on that. It's a Tricycle setup, so it will require 2 servos, and a bit of rigging for the steerable nosegear, but its been done by others so I think it'll turn out cool.
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Old 11-12-2008, 01:42 PM
  #431  
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AT LAST!!, Managed to maiden the "new" spit today!
Put an Align 430L 3550kv into it, with gearbox, running a 10 x 6 Master Airscrew. Also got a 9 x 9 prop (not tested yet), with the 10 x 6, performance was great! Pulled up into the vertical from launch, and just kept going!, did a few "vertical rolls" whilst climbing out too! Not blisteringly fast with this prop, but was just curious to see the vertical performance. It didn't dissapoint! Was going to try the 9 x 9 this afternoon, but it's just started bucketing down.

Watt meter peaked at 320 Watts initially under WOT, then settled to 260 Watts whilst flying. Current draw was only 29 Amps.

I've tried 4 different applications now, 2 with gearbox (1 stock, 1 brushless), and 2 with direct drive (2200kv and 2700 kv brushless)

There are pro's and con's of each setup.

It's a real pity that it's not possible to fit a really torquey brushless direct drive set-up that can swing a really big prop within the confines of the cowl, because it's quieter, and there's no gearbox to damage in the odd "mis-hap". So, until I find there is something that can give me the same performance from a 3S Li-Po, running through a 40 Amp ESC, I'll be sticking with the current set-up. Besides, I could really do with spending the time on upgrading the new Sapac F-22 raptor, and maidening the Eurofighter!
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Old 11-12-2008, 07:52 PM
  #432  
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Okay. Before i go flying my rebuild project i should ask for some prop advice. For now i am going to use the E-flite brushless 480 1020k motor.
With the added weight of the carbon fiber tubes and the retracts in the wings, does anyone have advice on what would be the best prop to use so it rips the air the best? It doesn't appear the Parkzone prop will work with this E-flite motor anyways, so i best get to ordering what i'd need.
From reading, it looks like people use a variety of 10 x 6's, 9x9's, 9x7.5's...
Just wondering what will work best for what i am using.
-Jay
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Old 11-12-2008, 07:58 PM
  #433  
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Jay,
Unless you have a wattmeter, I would think that question could only be answered by someone who has the same setup as you?
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Old 11-12-2008, 08:49 PM
  #434  
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Originally Posted by Aviator24 View Post
Jay,
Unless you have a wattmeter, I would think that question could only be answered by someone who has the same setup as you?
Yeah, I think the guy you need to ask is Mr. Radweld, as he opted (briefly as I recall) for an Eflite 480 outrunner. I think the verdict was that it was more torquey than speedy, but if you are not planning to break any records it works fine.

Maybe he will chime in on this one for ya. Or you could always crack open DriveCalc or the like and run some numbers.

GRU
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Old 11-13-2008, 04:58 PM
  #435  
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Default Optional Outrunner

FWIW I just saw a PZ Spit and the PZ FW-109 on saturday with the PZ T-28 motor and mount fly at the local field. Pilots said it is a bolt in with the stock firewall. They were very fast with unlimited vert. Don't know how long they will last, you could hear the wings making noise on hard pull-outs. Price is not all bad at $48.00 motor and $6.00 for mount.
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Old 11-13-2008, 11:46 PM
  #436  
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Originally Posted by mikidymac View Post
FWIW I just saw a PZ Spit and the PZ FW-109 on saturday with the PZ T-28 motor and mount fly at the local field. Pilots said it is a bolt in with the stock firewall. They were very fast with unlimited vert. Don't know how long they will last, you could hear the wings making noise on hard pull-outs. Price is not all bad at $48.00 motor and $6.00 for mount.
Hmmm . . . There's a thread here

http://www.rcgroups.com/forums/showthread.php?t=855934

which suggests that the stock motor isn't able to provide "unlimited vertical", heck, even the "upgrade" motors don't appear to offer unlimited vertical. I'd always be sceptical about what people "say" their model "can" do. If it can do it, how come they didn't show you it ??

Sorry, just playing "Devil's advocate"!

The info here:

http://www.modelflying.co.uk/news/article/mps/uan/452

States that the standard T-28 motor is a 960kv brushless, running through a 25A ESC, giving 18 Amps at Full Throttle. That only equates to 199 Watts. That's not going to give anyone "unlimited vertical" in this model!
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Old 11-13-2008, 11:57 PM
  #437  
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Ok, I might not be understanding unlimited vertical but I can say that when the spit and FW were pointed up they would keep climbing until it was almost out of sight then he brought it back down so I guess it would keep going.
I was just offering another brushless obtion if you have a spare T-28 motor around as some of us do.
I watched it with my own eyes and saw the motor through the cowl.
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Old 11-14-2008, 12:22 AM
  #438  
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hey, no problem!! models that have already got decent energy levels (i.e flying straight and level at full power), can often appear to have "unlimited vertical" as they transition to vertical flight, whereas all that's really happening is that they are trading speed for height, unless of corse, they have in excess of a 1:1 thrust:weight ration, in which case they really would have "unlimited vertical"

Based on the info on the motor here:

http://www.rcgroups.com/forums/showp...postcount=1724

MotoCalc gives the following:

MotOpinion - Untitled
500ft above Sea Level, 29.92inHg, 57F
Motor: Parkzone T-28 960kv; 960rpm/V; 0.96A no-load; 0.045 Ohms.
Battery: 1 Imax 2200mah Spitfire (20C); 3 cells; 2200mAh @ 3.7V; 0.0114 Ohms/cell.
Speed Control: Parkzone 25A ESC; 0.003 Ohms; High rate.
Drive System: Direct Drive 1:1; 9.5x7.5 (Pconst=1.31; Tconst=0.95) direct drive.
Airframe: 1 Parkzone spitfire; 252sq.in; 38.8oz RTF; 22.1oz/sq.ft; Cd=0.05; Cl=0.44; Clopt=0.54; Clmax=1.07.
Stats: 97 W/lb in; 81 W/lb out; 23mph stall; 33mph opt @ 55% (38:53, 77F); 36mph level @ 59% (34:34, 78F); 1447ft/min @ 29.9; -311ft/min @ -6.1.
Power System Notes:
The full-throttle motor current at the best lift-to-drag ratio airspeed (22.7A) falls approximately between the motor's maximum efficiency current (14.8A) and its current at theoretical maximum output (114.4A), thus making effective use of the motor.
Possible Aerodynamic Problems:
The diameter (9.5in) to pitch (7.5in) ratio is less than 1.5:1, which will result in reduced propeller efficiency at low speeds (the propeller is stalled). Although this is not likely to affect flying characteristics, it may make take-off or hand launching difficult.
Aerodynamic Notes:
The static pitch speed (61mph) is within the range of approximately 2.5 to 3 times the model's stall speed (23mph), which is considered ideal for good performance.
With a wing loading of 22.1oz/sq.ft, a model of this size will have a very high flying speed, requiring the undivided attention of an expert pilot. The high weight will provide good penetration, even in strong winds.
The static thrust (31.3oz) to weight (38.8oz) ratio is 0.81:1, which will result in very short take-off runs, no difficulty taking off from grass surfaces (assuming sufficiently large wheels), and steep climb-outs.
At the best lift-to-drag ratio airspeed, the excess-thrust (18.8oz) to weight (38.8oz) ratio is 0.48:1, which will give steep climbs and excellent acceleration. This model should be able to do consecutive loops, and has sufficient in-flight thrust for almost any aerobatic maneuver.
General Notes:
This analysis is based on calculations that take motor heating effects into account.
These calculations are based on mathematical models that may not account for all limitations of the components used. Always consult the power system component manufacturers to ensure that no limits (current, rpm, etc.) are being exceeded.

18.8oz of thrust versus approximately 38.8oz of aircraft. A nice upgrade, but not blistering.
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Old 11-14-2008, 12:33 AM
  #439  
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p.s., feel free to substitute "course" for "corse", and "ratio" for "ration", unless, of corse, yu carnt spel liyke mi.
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Old 11-14-2008, 01:59 AM
  #440  
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I can figure out what mikidymac meant. Where did you get the 38.8 oz AUW for a PZ Spitfire? Mine weighs 24.6 0z with a TP 2100 and a 1190 kv 2808/24 AXI outrunner motor / 9X7.5 prop / 40a esc. What does your chart say about that?

Originally Posted by abagnalejr123 View Post
hey, no problem!! models that have already got decent energy levels (i.e flying straight and level at full power), can often appear to have "unlimited vertical" as they transition to vertical flight, whereas all that's really happening is that they are trading speed for height, unless of corse, they have in excess of a 1:1 thrust:weight ration, in which case they really would have "unlimited vertical"

Based on the info on the motor here:

http://www.rcgroups.com/forums/showp...postcount=1724

MotoCalc gives the following:

MotOpinion - Untitled
500ft above Sea Level, 29.92inHg, 57F
Motor: Parkzone T-28 960kv; 960rpm/V; 0.96A no-load; 0.045 Ohms.
Battery: 1 Imax 2200mah Spitfire (20C); 3 cells; 2200mAh @ 3.7V; 0.0114 Ohms/cell.
Speed Control: Parkzone 25A ESC; 0.003 Ohms; High rate.
Drive System: Direct Drive 1:1; 9.5x7.5 (Pconst=1.31; Tconst=0.95) direct drive.
Airframe: 1 Parkzone spitfire; 252sq.in; 38.8oz RTF; 22.1oz/sq.ft; Cd=0.05; Cl=0.44; Clopt=0.54; Clmax=1.07.
Stats: 97 W/lb in; 81 W/lb out; 23mph stall; 33mph opt @ 55% (38:53, 77F); 36mph level @ 59% (34:34, 78F); 1447ft/min @ 29.9; -311ft/min @ -6.1.
Power System Notes:
The full-throttle motor current at the best lift-to-drag ratio airspeed (22.7A) falls approximately between the motor's maximum efficiency current (14.8A) and its current at theoretical maximum output (114.4A), thus making effective use of the motor.
Possible Aerodynamic Problems:
The diameter (9.5in) to pitch (7.5in) ratio is less than 1.5:1, which will result in reduced propeller efficiency at low speeds (the propeller is stalled). Although this is not likely to affect flying characteristics, it may make take-off or hand launching difficult.
Aerodynamic Notes:
The static pitch speed (61mph) is within the range of approximately 2.5 to 3 times the model's stall speed (23mph), which is considered ideal for good performance.
With a wing loading of 22.1oz/sq.ft, a model of this size will have a very high flying speed, requiring the undivided attention of an expert pilot. The high weight will provide good penetration, even in strong winds.
The static thrust (31.3oz) to weight (38.8oz) ratio is 0.81:1, which will result in very short take-off runs, no difficulty taking off from grass surfaces (assuming sufficiently large wheels), and steep climb-outs.
At the best lift-to-drag ratio airspeed, the excess-thrust (18.8oz) to weight (38.8oz) ratio is 0.48:1, which will give steep climbs and excellent acceleration. This model should be able to do consecutive loops, and has sufficient in-flight thrust for almost any aerobatic maneuver.
General Notes:
This analysis is based on calculations that take motor heating effects into account.
These calculations are based on mathematical models that may not account for all limitations of the components used. Always consult the power system component manufacturers to ensure that no limits (current, rpm, etc.) are being exceeded.

18.8oz of thrust versus approximately 38.8oz of aircraft. A nice upgrade, but not blistering.
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Old 11-14-2008, 02:03 AM
  #441  
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Default This does not sound right to me either?

I have the PKZ Corsair. This has the same motor as the T-28 if I am not mistaken? I get about 240 watts outta this according to my Wattmeter. I have a 3550 KV brushless running through the stock 3:1 gearbox on my Spitfire. Pulling 440 watts outta this setup. Even with the same prop and battery, I am getting more than 50% power outta my Spitfire. Even so, it does not have "unlimited vertical". If it did, I could launch it like a helicopter. Not an option. While my Spitfire is a rocket, I am certain it would not be nearly as fast with the setup you describe. The numbers just do not add up.
Sorry...


Originally Posted by mikidymac View Post
Ok, I might not be understanding unlimited vertical but I can say that when the spit and FW were pointed up they would keep climbing until it was almost out of sight then he brought it back down so I guess it would keep going.
I was just offering another brushless obtion if you have a spare T-28 motor around as some of us do.
I watched it with my own eyes and saw the motor through the cowl.
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Old 11-14-2008, 05:18 AM
  #442  
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Default Retract photos

Here are some quick photos of how i installed the Alfa retracts into my Parkzone Spitfire wing.
Photo 1 shows the holes already cut and cleaned up by lining the holes with left over green film from a damaged wing.
Photo 2 shows one of the retracts and wheel installed.
Photo 3 shows the retact and wheel down.
Photo 4 shows how flush it fits into the wheel well.
Photo 5 shows the top wing and how installed the carbon fiber tubes,
which are actually carbon fiber arrow shafts that i modified to use. (much cheaper in $$$!! Look at your local Wal-mart or sporting goods store).
Because of the retracts /where the servo sits, you'll have to measure carefully so as to not cut into your wheel well, and why you have to install the tubes at a slight "V". You'll have to put just a slight bend into your aluminum coupler.
I hope the photos work!



<img src="[media]http://img252.imageshack.us/img252/9322/bottomwing1em1.jpg[/media]" alt="Image Hosted by ImageShack.us" />
<img src="[media]http://img252.imageshack.us/img252/8707/wingbottom2ze3.jpg[/media]" alt="Image Hosted by ImageShack.us" />
<img src="[media]http://img252.imageshack.us/img252/9192/wingbottom3ul0.jpg[/media]" alt="Image Hosted by ImageShack.us" />
<img src="[media]http://img252.imageshack.us/img252/1300/wingbottom4yy6.jpg[/media]" alt="Image Hosted by ImageShack.us" />
<img src="[media]http://img252.imageshack.us/img252/1624/wingtopov9.jpg[/media]" alt="Image Hosted by ImageShack.us" />
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Old 11-14-2008, 07:06 AM
  #443  
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Originally Posted by SpitfireTrembly View Post
Here are some quick photos of how i installed the Alfa retracts into my Parkzone Spitfire wing.
Photo 1 shows the holes already cut and cleaned up by lining the holes with left over green film from a damaged wing.
Photo 2 shows one of the retracts and wheel installed.
Photo 3 shows the retact and wheel down.
Photo 4 shows how flush it fits into the wheel well.
Photo 5 shows the top wing and how installed the carbon fiber tubes,
which are actually carbon fiber arrow shafts that i modified to use. (much cheaper in $$$!! Look at your local Wal-mart or sporting goods store).
Because of the retracts /where the servo sits, you'll have to measure carefully so as to not cut into your wheel well, and why you have to install the tubes at a slight "V". You'll have to put just a slight bend into your aluminum coupler.
I hope the photos work!
Yeap, they work, but the HTML formatting isn't necessary (WattFlyer/vBulletin does it automagically).

Very cool sir. I like the attention to detail in laying in the laminate from the dead wing in the wells. Bravo.

Did you fill the gap atop the CF shafts before you replaced the covering? I used a judicuously applied amount of Vinyl spackle to seal the spar in and then replaced the covering. Worked pretty good and I didn't have to lay down a big oogly strip of packing tape over an open recess.

Get some video of 'er taking off and landing

GRU
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Old 11-14-2008, 08:53 AM
  #444  
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Thanks for the compliments on the detail work GRU! (you may need to help me on how i go about posting photos on here. I couldn't figure it out!)
When i first started thinking about doing the retract project (and if it was even possible) i saw the YouTube video where the guy did the tri-cycle landing gear on the PZ T-28 trainer (like you are wanting to do) and how ugly he left his install. That's why i saved the pre-colored film from my damaged wing, so i could have a much cleaner install on mine.
That guy could have cleaned his up with even some white paper or thin white construction paper. But i'm an artist and a very detailed one to boot, so even though i stepped out these landing gear OUT maybe a scale inch more than an actual Spitfire (And stepped back a bit because of where the PZ Spitfire Aileron wires run) I was trying to do it as clean and true to the real thing as i felt it could be done.
Thanks for your advice on the CF tube advice. I've been pondering how to best do THAT install more cleanly than the 2 inch packaging tape install like others have done. I cut just through the plastic film , peeled it back enough to work. Then i left an 1/8th inch ridge that i could re-glue the film back down to, rather than need the tape cover up.

But i like your idea for filling in that void left. There might be a lighter alternative though. It's a kids crafty/scultping toy i believe they call FLOAM (if i remember right.). It's like 50% styrofoam beads and what i'd compare to "Super Hair Gel". Once the water evaporates out of the hair gel type stuff, the mix of gel and styro holds its shape. That might be a lighter alternative to filling in that void??? It's just an idea.
If i can find it i'll give that a try and report the results. I think it'd be lighter than any kind of glue.
I was just trying to find a cheaper alternative for my Carbon fiber spar install. I thought about using parts from a kite. I also thought about using rods from a camping tent. Then i saw the CF arrows! I thought, "That'll WORK!" It's a bigger millimeter tube, But not that much.
So you'll have to remove more foam, but you are still adding a LOT, A LOT of strength to the wing with little additional weight. These things are as light as can be!

And it's a much cheaper way to add the strength than anything i see advertised on E-Bay, or advertised on Hobby-Lobby type places. Just go to Wal-mart or a sporting goods store and you can have the same thing with a modified Carbon Fiber Arrow Shaft and not have to pay the higher cost! I saved at least $15-20 bucks and didn't have to wait for it to be shipped from Hong Kong!

Or tear apart a cheap kite and use the plastic tubing. That'll also add more strength than the foam wing has.
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Old 11-14-2008, 05:52 PM
  #445  
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Originally Posted by SpitfireTrembly View Post
Thanks for the compliments on the detail work GRU! (you may need to help me on how i go about posting photos on here. I couldn't figure it out!)
No worries, it is relatively easy. While you are posting (usually after you have written the body of your post), scroll down below the smilies and look for a button that says "manage attachments". Click on that, and a window opens with multiple form fields, each with a "browse" next to it.

Click on browse, hunt around for the image in whatever directory you have them in on your PC, and select the particular image you want to upload.

Repeat until you have all of the photos you want to add listed, and then hit "upload". Takes a minute depending on your connection speed and the size of the images (if they are too large WF resizes them for ya) the next window you can add captions to your pictures, too. Then youjust close the second window, and you're done.



Originally Posted by SpitfireTrembly View Post
But i like your idea for filling in that void left. There might be a lighter alternative though. It's a kids crafty/scultping toy i believe they call FLOAM (if i remember right.). It's like 50% styrofoam beads and what i'd compare to "Super Hair Gel". Once the water evaporates out of the hair gel type stuff, the mix of gel and styro holds its shape. That might be a lighter alternative to filling in that void??? It's just an idea.

The vinyl spackling compound I am referring to is probably-after drying of course-lighter that the styrofoam it will replace. It is ultra-lightweight, so much so tha when you pick up the quart container from the shelf, if feels completely empty - and it dries rigid and very workable. A must have in the foamie enthusiast's toolkit. I can think of a hundred uses, but mostly for repairs like the one we are tlaking about, or dings/gouges in a leading edge. It can also be mixed with water into a sort of slurry and used to smooth out the 'beadiness' of EPS foam.

Keep us posted on the 're-maiden',

GRU
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Old 11-14-2008, 05:58 PM
  #446  
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I will just chime in to say GRU is right on target with this post.

Originally Posted by groundrushesup View Post
The vinyl spackling compound I am referring to is probably-after drying of course-lighter that the styrofoam it will replace. It is ultra-lightweight, so much so tha when you pick up the quart container from the shelf, if feels completely empty - and it dries rigid and very workable. A must have in the foamie enthusiast's toolkit. I can think of a hundred uses, but mostly for repairs like the one we are tlaking about, or dings/gouges in a leading edge. It can also be mixed with water into a sort of slurry and used to smooth out the 'beadiness' of EPS foam.

Keep us posted on the 're-maiden',

GRU
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Old 11-14-2008, 06:15 PM
  #447  
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GRU,
Ah i see the "manage posts/etc" stuff now! I'd just never scrolled down that far....lol!

Okay. Is the spackling compound that you are talking about a general hardware store item?

I think i know what you are talking about.
Many thanks for that advice and help!!!!
-Jay
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Old 11-14-2008, 06:31 PM
  #448  
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GRU,
i guess the better question to ask is, "who makes the spackling?"
If i have a brand name to go ask for that'll get me to filling me voids faster.
Many thanks in advance.
-Jay
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Old 11-14-2008, 06:32 PM
  #449  
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All your help is greatly appreciated GRU! Let me know who makes the spackling. -Jay
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Old 11-14-2008, 07:07 PM
  #450  
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Originally Posted by Gohmer View Post
I can figure out what mikidymac meant. Where did you get the 38.8 oz AUW for a PZ Spitfire? Mine weighs 24.6 0z with a TP 2100 and a 1190 kv 2808/24 AXI outrunner motor / 9X7.5 prop / 40a esc. What does your chart say about that?
I stand corrected, the error crept in because the standard PZ spit "flying weight" is quoted as 15oz (which is optomistic, considering the fact that the Li-Po you're using is obviously lighter than the standard battery) I didn't realise that motorcalc then adds the weights of the components TO the weight of the model, so theoretically, the individual weights of the components should be input as zero, and the actual completed "flying model weight" should be entered in the "model" section.

My "chart" states that, even given the revised flying weight of 24.6oz, a motor/prop combo producing 18.8oz of thrust would still not give unlimited vertical performance.

"Now. . . if I could just work out where I left that 14.2oz spanner. . . I'm sure I was using it recently on something." (exits stage left.)
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