P47 Thunderbolt 1,6 wingspanned by Graupner e-conversion

[Alex B]

As some will have read on another thread some weeks ago I ordered a P47 Thunderbolt by Graupner as a future project but due to my AT6 Texan death I've decided to start building this ARF kit slowly but without hesitating ;)

This P47 is very well finished as I'll show you on future pics when building's started...has retracts, and flaps as its wingspan is 1,6 mts. aprox and the final "gas" weight announced by manufacturer is 4.800 gr....as I'll be converting it to electric I'd like it to come out a little lighter...we'll see.

Ok now here comes the questions for me...I've got a spare AXI 4130/16 that was fitted on the AT6 Texan and was wondering if this could move this new model...no need for unreal speed this time as I like warbirds to fly sort of scale.

Well my idea for a set up is:

AXI 5320/28
Jeti 77 Opto Plus + Rx battery
Batteries: 2 Thunder Power packs of 5S4P at 10-12C and 8000mAh.
Prop APC E 15x10

Well any help will be more than appreciated.

Some pics to start things rolling !!!

Alex ;)

[Alex B]

Any ideas on which batteries and prop I should be using on this model or if I should choose another power plant ?

Link to Motor Specs (http://www.modelmotors.cz/index.php?id=en&nc=produkty_vypis&kategorie=m_neodym_ac&id_rady=axi_53&id_produktu=axi_5320_28&nazev_rady=Series%20AXI%2053%20GOLD%20LINE&hmotnost_rady=(495%20-%20652g))

Thanks,

Alex :)

[wolw]

Your'e a brave one aren't you ;) and I do envy you for daring :o

4800gr is a lot (for me), there are so many nice models that I've discarded just due to their weight.

Regarding batteries, Jeff (Vamooska (http://www.vampowerpro.com) ) is moving out 2S 2250mAh 12-16C LiPos for $18.95 each :eek: If you don't mind wiring (and soldering for 5S packs) your own parallel and series harness it's a very nice deal. The cells are matched and keeps balance very well. Weight is 406gr/4S 4500mAh, 510gr/5S 4500mAh, 612gr/6S 4500mAh.
I already had 8 packs (2 4S 4500mAh packs), I ordered 7 more this morning to get three 4500mAh packs of 4S, 5S and 6S to play around with :)

Vammy is great to deal with.

Looking forward to follow your build http://www.rcmf.co.uk/4um/Smileys/live/afro.gif

Almost forgot, good luck tomorrow.

//Peter http://www.rcmf.co.uk/4um/Smileys/live/smiley.gif

[SCALEFAN]

Peter,

The batteries are not listed at the price you quoted.

Al

[wolw]

No, you got to PM him (RCG price :D )

Sorry, forgot to add that :o

//Peter

[Alex B]

Thanks Peter for the info about Vampower batts...but I've been playing around with MotoCalc and I should use an 8S pack...but need to find the best option as I think to get some decent flight times I'll need 4P packs...I've got packs home but not too sure if they'll do the job...anyway would like the experts opinion on this as I might be pushing the motor to the limits ??? :confused:

I'll wait for some input from Carlos and see if he will kindly help me on this one...no hurry on building or flying so I better make the right decision on power set up and then start building...

For instance I'm not too sure which prop I should be using for a model this size...and that's going to make me use this motor or purchase the bigger one...hopefully I'll be able to save some cash and spend it on batteries instead :p

Alex :D

PS: I'm not too sure if I'm brave or suicidal :D :D :D ...right now I'm finishing balancing and fitting a new TP 6S3P pack to the F4U Corsair for tomorrow...should get about 40 minutes or so flight times if throttle used properly :rolleyes:

[wolw]

You're brave http://www.rcmf.co.uk/4um/Smileys/live/wink.gif

I'm not ready fo +6S yet, but all my packs are 2S 4500mAh (and one 1S 4500mAh) so I could get a 15S 4500mAh pack :eek: quite easy by just wiring a serie harness.

Let's see 15S @ 50A = ~3000W I wonder if my son would like to fly, or maybe one of the cats ;) :D

//Peter

[Alex B]

Peter it's not being brave but the motor specs otherwise won't turn the right prop :D

Definitely need a 8SxP pack to get this bird flying nicely and speedy...need to finally make my calculations but I think that's the only way to go with the AXI 4130/16...the 4130/20 would work better but I'm not going to spend the money for the sake of it...will think on it with my pillow :)

Peter get a nice pack for your big bird and you'll love it !!! but don't fit your son in it :p

Alex ;)

[guapoman2000]

Alex,

Wow....I just happen to stumble across this thread...I had no idea what you where up to....

Ayyy Dios mio....(Oh, My Lord).....4800 Grams = 11 lbs., ayy ya yaaaieeee! :D

Better have a good setup for both thrust and "Airspeed" and a spare tail hook for landing.

No, seriously, take a look at the Glow Section and see if anyone has this model with Glow and read up on it to see how it's flight characteristics and then, you can judge in what manner you need to setup your power system for to make it fly even better! ;)

[Alex B]

I will definitely get all the info I can on the model flying style...but I've owned the small versions and is a gentle flyer...nothing like the AT6 at all...has huge wide wings to support the model at very low speed so landing and flying should not be that difficult this time...the problem is that this motor needs a lot of battery input to get the best out of it and 8 li-po packs is the limit of it...I'm wondering if that will kill the motor sooner than it should ???

Well now time to finish setting up the F4U for tomorrow and then have a deep reading through the gas section.

And yes 4,8 kg. is a bit scaring but hell...let's give it a go hey ???!!! :eek: :p :p

Thanks,

Alex ;)

[Alex B]

Well first post has been updated with final set up...I have the batteries which are actually going to be used for both the Cessna 182 only in 1 pack version and then the 2 packs for this plane...good !!!

Power system had to be updated after weighting all parts as it seems that with this set of batteries the overall weight will be of 4,8 + motor...so at then end it should be a 5,3 kg. bird :eek:

Alex ;)

[Alex B]

Forgot to mention that the wing loading will be of 31,4 oz/sd.ft and the pitch speed should be 75 mph.

Flight time predictions on motocalc show 56 minutes at full throttle so plenty of batteries for a nice sunday morning flying ;)

[guapoman2000]

Forgot to mention that the wing loading will be of 31,4 oz/sd.ft and the pitch speed should be 75 mph.

Flight time predictions on motocalc show 56 minutes at full throttle so plenty of batteries for a nice sunday morning flying ;)

Alex,

Make sure you take it easy with this model and don't horse it around too much as at this wing loading she will not be very forgiving. :o

Best of luck!
Carlos :cool:

[Alex B]

Thanks Carlos I know it really sounds a lot but compared to my Cessna or ex-AT6 is only 3-4 oz heavier per sq/ft and stall speed is only 1 mph higher than Cessna...but definitely will fly it nice and taking care of it not to play to much with it as a start until I get used to it and check everything at hundred miles from solid earth :p

Alex :D

[thunder1]

I see you mention a 4130/16 but then say you're going to install a 5320/28. Which are you going to install? You could probably cut down the weight by 1.5 lbs by going with the 4130 and 6s2p setup.

Since the wingspan is approx. 63" I'd say this model is pretty much the same as the .60 sized H9 P-47 which measures 65". The wing area on that one is listed as 727.5 sq in. The wing area listed on this model is 50 dm which works out to around 770 sq in. I'm not sure how they figured that out. But the horizontal stab shouldn't be included in the wing area.

Anyways at 5.7Kg or 12.5 lbs with a wing area of 770 squares, you're looking at 37 oz/ sq in wing loading. But if you use the wing area of the H9 P-47 you're really looking at nearly 40 oz sq in.

Sounds like flap territory to me;-)

[Alex B]

Thunder1 I'm finally going to go for the 5320/28, wing loading is what motocalc showed after I typed all the info of empty weight as per programme demand, wing area and wing span given by manufacturer.

It has flaps by the way...otherwise I'd say it would be unflyable :eek:

Thanks for the input.

Here are some pics of tail and elevator construction and 2 pics along the F4U I built from Phoneix Models for size comparisson, this one is larger and fatter :p

Alex ;)

[thunder1]

It looks about the same size as the H9 P-47. Most of those end up weighing 8-9 lbs. The motor of choice is the 4130/16 or E-Flight Power 60. But at your weight, those are out of the question.

Your's looks very well built. Definitely a good glow model.

I'm a little leery of the wing area listed on the box cover. What's the root chord and tip chord (at the aileron tips)?

[guapoman2000]

Here's a neat wing loading calculator !! :)

http://www.coloradogliders.com/wingloadingcalculator.htm

[Alex B]

Now who's going to give a lesson on how to messure all those parameters ??? :confused:

I haven't got a clue my friends but if somebody gives me a hand I'll fill in the info and tell you.

Thanks,

Alex ;)

[guapoman2000]

Now who's going to give a lesson on how to messure all those parameters ??? :confused:

I haven't got a clue my friends but if somebody gives me a hand I'll fill in the info and tell you.

Thanks,

Alex ;)

Alex,

It is rather simple.....on a non-rectangular wing airfoil...such as your model and that of say a SpitFire...you need to measure across the wing cord with say 4 - 5 measurements and average them out.....this is what you input....

Carlos

[thunder1]

Here's a measurement that will be pretty close. Measure the red lines. Those are the tip and root chords. The tip chord should be measured at the point where the leading edge starts to curve.

Then enter those numbers as if the wing has the planform indicated in green.

[wolw]

It really looks nice :)

Those flaps is going to be useful giving you valuable lift at landings.

//Peter http://www.rcmf.co.uk/4um/Smileys/live/cool.gif

[Alex B]

Ok guys once I get to the wing I'll messure everything as accurate as possible and then calculate the real wing loading.

Peter it is nice although I would have liked the older version but wasn't available except on a bigger size and fiberglass fuse...anyway once I get used to fly this sort of birds I'd like to built a 2+ mt. warbird as my final project.

Thanks a lot to everyone for your input.

Alex ;)

PS: Post 11 edited with new final weight due to a little calculation error.

[Alex B]

Some pics of battery testing and size reference and tailwheel ;)

Alex

[Alex B]

Here are tail and elevator control horns...good quality items :)

[thunder1]

That hardware does look durable. But one of the drawbacks of not having the control horn hinge point (where the clevis joins the horn) centered over the hinge line is that you're going to have uneven throws (differential)

If you have a computer radio you can set the endpoints to even the throws out. Otherwise the up/right travel will be different than the down/left travel. As it is it looks like the up/right travel is going to be greater than the down/left travel. Probably no big deal.

I highly suggest using the little plastic clevis keepers as on such a heavy plane the clevis can weaken and pull through the threads and/or open at the horn end. All it takes is a slight bump of the control surface to make this happen.

[SCALEFAN]

There looks like plenty of movement available in any direction, but this looks like severe over kill.

The big question, how strong do you need the parts to be? If you hold back the rudder and elevator with your two fingers you will cause the wood to crack and break with just the normal servos and hardware. This is not a 3D plane, don't waste your money on any more heavy duty stuff. It's better to have some flex, it will save the wood.

Like I said, the wood underneath will break if the control pressure is too great, even from standard $13.00 servos.

Al

[wolw]

he big question, how strong do you need the parts to be

It's the Graupner way.
Like a Mercedes Benz, built to last ;)

Alex, I think it looks great.

This is the tailplane on my Graupner Extra 300

//Peter

[Alex B]

Exactly that hardware came with the kit so I thought it would be ok if they design it for this bird ??? and what the plastic clevis keepers ??? never heard of that before.

Thanks,

Alex ;)

[SCALEFAN]

I think he meant the plastic clevis keeper to be the fuel hose type.

Ya know, you cut off a 1/4 inch piece of fuel hose and slide it over the clevis.

Hey, if the hardware came with the kit, great. No problemo. I'm wrong and will be willing to admit it.

I made the mistake of buying this Robart stuff that was so heavy duty that I threw it away. I belive in severe over kill, but, the super heavy duty stuff that got shipped to me looked silly on a Hangar 9 Corsair. It looked as silly as if I bought cabinet hinges at Home Depot and put them on the plane.

All kidding aside, I saw the heavy duty stuff on extra giant scale 3D planes, but not on balsa elevators or rudders that can crack easy.

Keep up the good work, how much time do you estimate that you have left untill completion? I want to see videos of this baby flying.

Al

[Alex B]

Al great idea that of fitting some retaining rubber stuff on clevisses...mmmm...I'll do it just in case....completion who knows...just started this eve and I'm waiting on some Esprit Model stuff like the motor mount and rx batt switch with charge indicator led, it should take a week to arrive and motor+esc should show up on monday or tuesday...so I guess if Esprit's stuff arrives late next week I could try and fly it on sunday morning...only thinking about it scares me to death at the very moment.

Anyway no pain no gain, isn't it ??? :D ;)

Pics of tail and elevator in servo tray...now let's get into aileron and flaps servos.

Alex ;)

[Alex B]

Well here's 3 pics showing the aluminium spar that will hold wings together and 2 for overall bird size reference.

It really is impressive with those massive fat wings...beautifull plane.

Alex :D

[Alex B]

Wing holes for aileron and flap servos and retracts location. There's a thread in each wing to ease servo wire enrouting through the wing.

Alex ;)

[Alex B]

Few progress since last post, now working on it again...some pics of servo supressor, and aileron and flap installation.

One question though I've got this plastic sheet with wheel wells on it and some air intake ??? but no information on instructions regarding these bits...any idea where to fit them ?

Thanks,

Alex ;)

[wolw]

Aren't they to be put in the wheel well so it looks nice when landing gear is out ?

//Peter http://ashtekelectronics.com/pics/copter.gif

[guapoman2000]

1. I am suprised that this ARF did not come with Aileron wing Servo covers
2. Did not come with better instructions.

The Wheel wells are part of that Plastic Sheeting....perhaps you need to cut them out carefully and trim and install inside the wheel wells of your retracted gear.

I tried to make a search for your model and the only one that came up was this:

http://www.modelflight.com.au/manuals/pdf/hanger-9/P47_Manual.pdf

[Alex B]

Could well be for that but I find them rather huge at the upper end ??? :confused:

Thanks Peter,

Alex ;)

[guapoman2000]

Could well be for that but I find them rather huge at the upper end ??? :confused:

Thanks Peter,

Alex ;)

No sweat.......I would paint the inside of the wheel well if it is going to be a science project dealing with that plastic parts sheet. I would use acrlyic paint that matches the exterior. ;)

[SCALEFAN]

Looking at the wing, it looks like everything will look good without the plastic wheel well covers. It's a project to remove the wheel well covers if you have to work on the retract mechanism.

I don't know if it's right or wrong, but, whenever wood is exposed, like inside the wheel wells, I coat the wood with CR. It makes it harder and less likely to break. Then paint it to match the plane, it will look good that way. Besides, looking back in memory, I don't think full size WWII planes have wheel well covers, the gear doors cover most of the hole.

Al

[Alex B]

Carlos thanks for the link to Hangar 9 P47...the wheel wells are small and angular...so the pieces on my plastic sheet must be..

Al these retracts well covers which are much like the ones on the AT6 Texan are not a problem to fit as you'll see in the pic attached...although yes they'll make impossible a future inspection on piano wires if something goes wrong...but the finish look is nice.

Carlos the other bits should be the wheel well covers but they're huge..so I suppose they're provided for modeller to trim out ?

And yes there's wing servo covers :D

Alex ;)

[Alex B]

Wheel well are a bit out of shape comapred to scale plane so I've got 2 opitons...built a new set from scratch using balsa or whatever I have handy...or trim the plastic bits to shape.

Alex :rolleyes:

[Alex B]

Well this is what I've come up with so far to make it look more scale like ;) not 100% scale but much better than the plastic supplied...I think ???!!!

Alex :D

[thunder1]

That looks better. Just make sure you secure them well. I've had the gear doors shift around in flight and keep the landing gear from locking in place.

[guapoman2000]

Those Wheel skirts are very scale looking.....good job Alex! :p

[SCALEFAN]

Hey Alex, nice job. However I would still get rid of the plastic.

Al

[guapoman2000]

Hey Alex, nice job. However I would still get rid of the plastic.

Al

That's what she said... :D

[Alex B]

How did you know Carlos ??? I've just known my wife and I are expecting a baby :D ...it's true !!!

And yes I won't be using those plastic things instead I think I'll work on the balsa and might lay some fiberglass on it...not too sure yet.

Alex ;)

[wolw]

How did you know Carlos ??? I've just known my wife and I are expecting a baby :D ...it's true !!!

Alex ;)

Oh dear, Congratulations :)

I must warn you that your available timefor building planes is going to be seriously decreased ;)

Cheers,

Peter :)

[Alex B]

Thanks Peter...and yes I've already been warned by my older brother and his wife and my own wife :p

But I'll find the way to have some time to build and fly !!! I hope so :D

Alex

[Alex B]

Well here's the beast that will swing the prop on this project...I'm going to take it easy before flying it and make sure everything is ok flight after flight...I don't want no more surprises !!!

Alex ;)

[Alex B]

This project has been stopped while I await for Esprit Model parts to complete the motor installation and other bits...will report as soon as I get them and things get closer to the finished product...I think it will take me another 2 weeks to complete it as I want everything to work nice and smooth on this heavy duty beast :)

Meanwhile I'll start my next project (Kyosho Messerschmitt bf109E) using the electronics I had on the R.I.P. F4U Corsair.

Alex ;)

[guapoman2000]

Alex,

Good choice on Esprit Models....I was there just yesterday and bought a couple of items.

Hey, did you ever figured out the Wheel Wells for your model? Here's a picture from NitroPlanes for one ZERO RC Model that shows how they installed the Retract Wheel Wells. ;)

[Alex B]

Thanks Carlos I was actually thinking on how to finish the retract wells so they could be taken out in case of need...great idea I'll use small screws on them...and the wheel wells are the easiest way to go...simple and effective.

Thanks for that shot...

Regarding Esprit I've ordered some other things in the past and never had a problem...just that thye're not as fast processing orders.

By the way do you know if Astro Flight it's open ??? I ordered some stuff through their site on the 10th. and have had no news from them :confused:

Alex ;)

[guapoman2000]

By the way do you know if Astro Flight it's open ??? I ordered some stuff through their site on the 10th. and have had no news from them :confused:

Alex ;)

Open for business? Sure! They are very busy and usually you have to leave a message "or" you can e-mail them at:

info@astroflight.com

[Alex B]

Thanks Carlos I had already sent an e-mail on the 10th and re-sent it today and see if I'm luckier this time :rolleyes:

Alex

Just received a reply from Michelle saying order will ship today...yihaaa :)

[Ed Lyerly]

Alex,
The 4130/16 is really a 6S setup (1250 to 1350 watts at 60-65 amps) . I've seen this fly a 10 lb (4.5 kg) plane pretty well, and you should be around 11 lbs (5.0 kg) with a 6S pack. I think you will roast the motor if you go 8S. IMHO, A 4130/20 would be better if you go 8S
Ed

PS ... with the 5320/28 on 10S, you will need an 17" prop to get the amps up to 50 or so ....do you have that much prop clearance ?

[guapoman2000]

Alex,

To clear up things......which motor are you going to use from post #50 ?

http://www.rcgroups.com/forums/showpost.php?p=6055928&postcount=50

:confused:

[guapoman2000]

Per Model Motors Web Site:
http://www.modelmotors.cz/index.php?id=en&nc=produkty_vypis&kategorie=m_neodym_ac&id_rady=axi_53&id_produktu=axi_5320_28&nazev_rady=Series%20AXI%2053%20GOLD%20LINE&hmotnost_rady=(495%20-%20652g)

No. Of cells max. 32
max. 10s Li-Poly
RPM/V 249 RMP/V
Max. efficiency 92%
Max. efficiency current 10 - 36 A (>85%)
No load current / 10 V 1,4 A <--- Means @ 10 Volts constant! :)
Current capacity 50 A/60 s
Internal Resistance 57 mohm
Dimensions 63x54 mm
Shaft diameter 8 mm
Weight with cables 495 g
Recomended model weight 4000 - 8000 g
Recomended prop without gearbox 8s Li-Poly 23"x11"APC-E
10s Li-Poly 18"x12"APC-E
Recomended speed controller JETI ADVANCE 77

--------------------------------------------------------------------
Models Parameters:
Wing Span: 1600mm = 63 inches
Wing Area: 50 sq.-m. = 538.2 sq.-in.
Weight: 5300grams = 12.27 lbs.

Based on using some larger and more robust Li-POLYs such as the KOKAM 3200SHD with a maximum 20C discharge rate, they are on the heavy side at 2.83oz. each cell so, they will load down the model but, you get the full advantage of motor performance as these cells will not starve the motor when it comes to AMP draw. ;) I am using 10S2P and the APC "Pattern" 15X12 propeller. :)

Just take a look at your airspeed..... :eek:
Static pitch speed (90mph) is within the range of approximately 2.5 to 3 times the model's stall speed (33mph), which is considered ideal for good performance.

Also, take a look at your static thrust-to-weight!!!! :eek: Really, no need for any larger propeller as you need airspeed on this very heavy wing loaded model ;)

Static thrust (176.1oz) to weight (146.2oz) ratio is 1.2:1, which will result in extremely short take-off

[wolw]

With a wing loading of 39.1 oz/sq.ft, a model of this size will have a very high flying speed, requiring the undivided attention of an expert pilot
This model will probable be able to perform a hover or torque roll

Jeezz, you got your self a handfull, Alex ;)

//Peter :p

[Alex B]

Carlos thanks again...no I won't be using a huge prop on this project unless it's completelly necessary...I mean for scale looks otherwise I'm pretty sure that with the AXI 5320/18 and a 15x10 or 15x12 prop I should get away very well.

Batteries will be 2 packs of Thunder Power at 10-12C rating of 8000mAh capacity and built on 5S4P each.

Motocalc shows about 1000-1200 Watts using this configuration so should be more than enough for this bird I think.

Well I won't be reporting much progress until I get Esprit's motor supports and I figure out how to fix batteries inside and other bits like finish the landing gear wells.

Alex ;)

[Alex B]

Jeezz, you got your self a handfull, Alex ;)

//Peter :p

I told you not to buy the FUNTANA/KATANA.... :p

[wolw]

I told you not to buy the FUNTANA/KATANA.... :p

I'm starting to think that mine might just flop around if there's some wind, projected wingload 17.49oz/sq.ft :confused:

My next is decided anyway (your fault ;) ) Seagulls P-51 :D

//Peter :)

[guapoman2000]

Carlos thanks again...no I won't be using a huge prop on this project unless it's completelly necessary...I mean for scale looks otherwise I'm pretty sure that with the AXI 5320/18 and a 15x10 or 15x12 prop I should get away very well.

Batteries will be 2 packs of Thunder Power at 10-12C rating of 8000mAh capacity and built on 5S4P each.

Motocalc shows about 1000-1200 Watts using this configuration so should be more than enough for this bird I think.

Well I won't be reporting much progress until I get Esprit's motor supports and I figure out how to fix batteries inside and other bits like finish the landing gear wells.

Alex ;)

Alex,

I am sure it was a typo.....you meant to type AXI 5320/28 as Model Motors does not make a 5320/18 :D Not yet at least.... ;)

With the use of 10S Li-POLY and trying to swing a larger propeller, MotorCalc gives some warnings about the motor temperature especially using a 16 or 17 inch diameters and different pitches....also, the airpseed deminishes.

Good to learn that you will try out the 15 incher first.....that Jug Head need airspeed :D

[guapoman2000]

Static thrust (176.1oz) to weight (146.2oz) ratio is 1.2:1, which will result in extremely short take-off

Lets not forget the above!!! :D For those that Love Thrust! :D

[Ed Lyerly]

Well, here is what E Calc says about the 15" prop vrs the 17" prop based on using the 5320/28 on 10S.
The 15x12 will fly it fine, but the 17x10 would be better :-). Model Motors own website says use an 18" prop with on this motor with 10S.
Ed

[guapoman2000]

Without filling this Thread with all kinds of Snap Shots of MotorCalc again.....

Alex,

Using 10S2P (Kokam 3200SHD (20C); 10 series x 2 parallel cells) and using the APC 17 X 10 Prop.

Here's what MotorCalc indicates as a precautionary warnings:

The full-throttle steady-state motor temperature (323°F) is extremely high, which will likely damage the motor unless full-throttle is used sparingly and cooling is good (even then, damage is possible).


The static pitch speed (70mph) is less than 2.5 times the stall speed (33mph), which may result in reduced performance at typical flying speeds and a low maximum speed. This situation is usually acceptable for an electric sailplane or other slow-flying model.
Pitch speed can be increased by using a higher pitched and/or smaller diameter propeller, a higher cell count, or some combination of these methods.
.

Alex, it's your heavy JUG HEAD we are talking about......I would certainly measure your Propeller RPMs with both just for you to see the difference in Propeller Pitch Speed ;)

[guapoman2000]

Per Model Motors Web Site:
http://www.modelmotors.cz/index.php?id=en&nc=produkty_vypis&kategorie=m_neodym_ac&id_rady=axi_53&id_produktu=axi_5320_28&nazev_rady=Series%20AXI%2053%20GOLD%20LINE&hmotnost_rady=(495%20-%20652g)

No. Of cells max. 32
max. 10s Li-Poly
RPM/V 249 RMP/V
Max. efficiency 92%
Max. efficiency current 10 - 36 A (>85%)
No load current / 10 V 1,4 A <--- Means @ 10 Volts constant! :)
Current capacity 50 A/60 s


Alex,

Recall......the above Maximum Current Draw.....as listed in Model Motors Web Site.....don't make me post those Videos of Chuck McHugh pushing his AXI 41XX series Outrunner with higher AMP draw than what that poor motor could withstand......it was a sad day at the field.... ;)

That was a wake-up experience for all of us at the Field that day and for Chuck McHugh it was time to rethink things about Maximums data posted at a Web Site.....

I rather errr on the conservative when providing recommendations! :rolleyes:

[guapoman2000]

Alex,

Here's one graph showing what happens when you place a large diameter propeller intended for a fast flying model....especially one that has a high wing loading..... ;)

Already at 60 MPH the Prop efficiency and that of the motor drops off something terrible.......can you say dump your battery pack energy into heat..... :o

[guapoman2000]

Alex,

One last thing......if your model will have a little over 35 oz./sq.-ft. of wing loading, I seriously doubt for one minute that the models STALL SPEED is 23MPH!!! This is more like a model that sports a wing loading in the mid 20's and not a heavy model like your P-47.

Certainly, you would need to determine for yourself, what exactly is the stall speed for your model if you don't trust either software that has been posted here. ;)

Here's what I am trying to point out...... :rolleyes:

Your models: Wing Area: 50 sq.-m. = 538.2 sq.-in. perhaps that's the error???? :confused:

[Ed Lyerly]

OK ..... have it your way :).
Not here to argue, just trying to provide advice.
Ed

[guapoman2000]

What? Did someone say something to me.... :D

Argue :confused:

More like having a discussion....what is the wing area in ENGLISH from 50dM??? :confused:

Anyone?

[Ed Lyerly]

Alex,

One last thing......if your model will have a little over 35 oz./sq.-ft. of wing loading, I seriously doubt for one minute that the models STALL SPEED is 23MPH!!! This is more like a model that sports a wing loading in the mid 20's and not a heavy model like your P-47.

Certainly, you would need to determine for yourself, what exactly is the stall speed for your model if you don't trust either software that has been posted here. ;)

Here's what I am trying to point out...... :rolleyes:

Your models: Wing Area: 50 sq.-m. = 538.2 sq.-in. perhaps that's the error???? :confused:

OH well ......

[guapoman2000]

Then perhaps 23 MPH Stall Speed is correct as it has lots of wing area....

Thereby, a 16 or even a 17 inch propeller assuming you measure AMP draw and Propeller RPMs could be a good choice.

Thanks Ed.....I would have never known such a metric value as deci whatever? :rolleyes: :o

I was using this on-line calculator and the small 'd' threw me off.... :) :D

http://www.sciencemadesimple.net/area.php

Wow....with that kind of wing area......she be a pussy cat, well you can not horse her around too much...but, she be a sweet flyer! :D

[guapoman2000]

Okay with the new (Correct Wing Area :o ) again thanks to Ed.... :D

Using 10S2P, and the APC 17 X 10 propeller! :eek:

Here's what my Motor Calc says: (Assuming an empty dry weight of 70oz.)

The static pitch speed (70mph) is within the range of approximately 2.5 to 3 times the model's stall speed (27mph), which is considered ideal for good performance.

With a wing loading of 27.2oz/sq.ft, a model of this size will have flying characteristics suited to the intermediate pilot, for use in calm to moderate wind conditions.

The static thrust (232.4oz) to weight (146.2oz) ratio is 1.59:1, which will result in extremely short take-off runs, no difficulty taking off from grass surfaces (assuming sufficiently large wheels), and vertical climb-outs. This model will probably be able to perform a hover or torque roll.

At the best lift-to-drag ratio airspeed, the excess-thrust (148.2oz) to weight (146.2oz) ratio is 1.01:1, which will give very steep climbs and incredible acceleration.

[guapoman2000]

Alex,

Whatever prop and combination of Battery cell count you use, make sure you measure all parameters.... ;)

Wow, can't wait to see the Video on this model...assuming your Video person can keep up with it! :D

Best of luck!
Carlos :cool:

[wolw]

Wing Area: 714 sq in (46.1 dm2) on my Funtana.

EDIT: Guess I'm slow (I'm at work) :rolleyes:

Great converter, Ed :)

Metric is the future :p

//Peter :p

[guapoman2000]

Wing Area: 714 sq in (46.1 dm2) on my Funtana.

//Peter :p

Geesh,

I guess those that deal with Metric are used to dealing with this 46.1 dm2 unit..... :o

I would have never realized... :o

[Alex B]

Carlos here's a screen print of details for this model...jezzz people we've all gone baloonnnnnsssss with messures and weight...I use metric but as motocalc can deal with both...easy going :)

The empty weight has been calculated to meet Motocalc components rules.

Prop size will be determined by scale look...of course I want it to fly :D

Alex ;)

[thunder1]

Alex, have you ever measured the wing to figure out wing area? The calculations that I used (H9 P-47's wing) puts you in the neighborhood of 40oz sq foot at 12.5 lbs AUW. For a 63" wingspan model that's a bit heavy. It'll fly like a warbird, that's for sure.

[wolw]

Geesh,

I guess those that deal with Metric are used to dealing with this 46.1 dm2 unit..... :o

I would have never realized... :o

1 Metre = 10 dm :)
1 Metre = 100cm ;)
1 metre = 1000mm :p

//Peter :D

[Alex B]

Thunder1 rest assured that before I fly this baby I'll do all the maths using the help you and Carlos gave me on post 20 and 21.

Alex ;)

[guapoman2000]

Carlos here's a screen print of details for this model...jezzz people we've all gone baloonnnnnsssss with messures and weight...I use metric but as motocalc can deal with both...easy going :)

The empty weight has been calculated to meet Motocalc components rules.

Prop size will be determined by scale look...of course I want it to fly :D

Alex ;)


Alex,

Wow, an empty weight of 110oz., that's almost 7lbs. :eek: What kind of wood did they use for this bird? Well, at least it is very rugged. :D

[Alex B]

Carlos I'm a bit concerned now because after taking some messures on the wings according to post 20 and 21 results differ from 250 to 290 wing cord average...it depends on which method I use...but the overall wing area doesn't match at all the one announced by manufacturer...so wing loading can go from 32 to 39 oz/sq.ft which is a bit scary :( ...and honestly no way I can make it clear or should I e-mail Graupner and ask them ???

ColoradoGlidders site estimates a 25 oz./sq.ft for fighters and I'm way over that....I want to :cry

The wood used on this model is very good as on the AT6 Texan...fully sheeted all over...great quality but a weight penalty I'd say :rolleyes:

Alex :confused:

[wolw]

Alex, the empty weight you put in motocalc (110oz) have you got it from putting it on the scale ?
110oz is Graupners calculated AUW with a slimer, and they aren't usually that far off.

Maybe you got the Tjernobyl version (clad in lead) ;) Sorry, bad joke, couldn't help it :o

//Peter :o

[thunder1]

110 oz is only 6.9 lbs. I'd say that's the empty weight of the airframe, exclusive of servos, motor, etc. OTOH, if the RTF weight is around 7 lbs, I'd be amazed and the flight qualities would be akin to a park flyer.

The H9 65" P-47s are coming in at around 8-9 lbs RTF and they fly very nicely, no flaps required.

Edit: From the box label the RTF weight is 4800g which is 169 oz or about 10.5 lbs.

[Ed Lyerly]

Alex said AUW would be 5.3 kg in post # 11. That is 11.66 lbs. With incidentals, I'm specularing the AUW at 12 lbs or 192 oz or 5.45 kg. Hopefully, the actual wing area will be 775 sq in as advertised. If not, the plot thickens. I will say that in the past, I have purchased european made ARF's (JR Models) that surprised me ....because they included the stab area in the wing area measurement. If that is the case here .... adjustments need to be made to performance calculations.
One option to reduce weight (as Carlos pointed out earlier) would be to use cells with less capacity. Switching from a TP 10S 4P 8000 mah pack to a 10 S 2P 4000 mah pack will shave 1.75 lbs or 28 oz off the AUW and still give respectable flights times.
Ed

[Alex B]

Ok I could try and put this fat bird on a diet using less capacity batteries with higher discharge rating...but then weight would be increased due to 20C batteries...they're heavier than Thunder Power 10-12C rating...and have a look at this Graupner Super Star ARF Glow Conversion RC Plane (http://www.hobby-lobby.com/superstar.htm) ain't this fat too...at least compared to mine I shouldn't be that far from that shown there...and it flies :D

Alex ;)

PS: forgot to mention that the overall weight will be around 5.100-5250 gr.

[Ed Lyerly]

Ok I could try and put this fat bird on a diet using less capacity batteries with higher discharge rating...but then weight would be increased due to 20C batteries...they're heavier than Thunder Power 10-12C rating...and have a look at this Graupner Super Star ARF Glow Conversion RC Plane (http://www.hobby-lobby.com/superstar.htm) ain't this fat too...at least compared to mine I shouldn't be that far from that shown there...and it flies :D

Alex ;)

PS: forgot to mention that the overall weight will be around 5.100-5250 gr.

Alex,
Thats good that the AUW turns out to be less than 12 lbs (11.2 lbs to 11.6 lbs) :). It should fly fine at that weight on the 10S 4P 8000's you have..... assuming the wing area is near what is advertised. I would fly it with what you have 1st. If it flies OK, but you determine it would be better at 1.75 lbs less, then you might consider the lighter weight batteries. You can compare the weights on the Esprit Model website.
On the Super Star comparison .... it has 30% more wing area (1009 vrs 775) and weighs only 15% more. Not really a good comparison, although interesting that they are recommending 10S and an 18x12 APC-E prop (I would estimate this would pull 60-65 amps).
Ed

[Alex B]

I suppose this bird is heavier than H9 one...hence why it needs flaps :rolleyes:

I'll try it with what I've got and then decide if it feels comfortable on air or not...viceless as the smaller versions...if it flies as well as the Alfa Model little warbird I'll be more than happy as I've tried that one on heavier set up than recommended by manufacturer and it's always flown easy and smooth...and landing is a pleasure due to the size of its wings compared to other warbirds on the same size.

Thanks to everyone for the input...and wonder why Hobby Lobby hasn't already done this conversion eventhough it's a new plane :confused:

Alex ;)

[wolw]

I actually had Graupners Superstar in mind when I though about the weight of yours, MFT (http://www.mft.nu/graupner/superstar/superstar.htm) got final AUW 4850gr/171oz 10.69lb, that's my local LHS. He went with a 4130/20 on 8S 4800mAh 1800W.

I get a lot of inspiration from there, they usually come out lighter electric than manufacturers glow AUW and a lot lighter than Hobby-Lobbys conversions.

//Peter :)

[guapoman2000]

4130/20 using 8S3P with those super light 1600mAH Li-POLY cells and swinging the large APC "E" 18 X 8 propeller for that Acrobatic model is perhaps okay at 11lbs., it's mid-wing and fully symmtrical wing airfoil is suited for this setup. However, the airspeed using such a low pitch is at best 43 MPH and certainly not recommended for the P-47 with a low wing warbird semi-symmetrical wing airfoil.

In previous discussions, the propeller size diameter and pitch has pretty much dominated this thread..... :rolleyes: However I am very serious about the exact wing area of this model....should the owner (Alex) not trust what is on the BOX "and" his manual calculations result in actual wing area of less than 700 sq.-in. "or" less than 50dM, I would certainly ask myself what is best for this warbird with flapps.

Presently, the Larger Model Motors AXI 5000 series has enough torque to swing perhaps up to a 17 inch propeller....I am still concern about the motor temperature by swinging this large propeller and 10S Li-POLY cells. Remember that it is all about TORQUE and the more TORQUE a motor has, especially an outrunner with lowest Kv and maximized Kt you then can have the best of both worlds (almost), THRUST and AIRSPEED at the cost of weight due to the additional cell count.

Making the airframe lighter by selecting a lighter motor to shave off 2 - 4 oz. and using lighter cells (more parallel required) may result in the same weight category anyway with an added headache of not being able to balance the model as now you have removed the nose weight :o Plus and most importantly, the AXI 4130/20 is really not suited to swing such a large 17 inch propeller while using 10S which is the required amount to obtain the necessary Propeller "Pitch" Speed. ;)

Specifications for the AXI 4130/20 at the Model Motors Web Site:
http://www.modelmotors.cz/index.php?id=en&nc=produkty_vypis&kategorie=m_neodym_ac&id_rady=axi_41&id_produktu=axi_4130_20&nazev_rady=Series+AXI+41&hmotnost_rady=(320+-+409+g)

[wolw]

You're the expert here Carlos :)
Guess I can harass you when I build the P-51 ;)

//Peter :)

[guapoman2000]

You're the expert here Carlos :)
Guess I can harass you when I build the P-51 ;)

//Peter :)


No expert.....I have had some experience myself and that of watching some RC buddies fail when they have Pushed their Brushless Motors (Outrunners) to the limit and it usually comes back to BITE you very ugly like :o

Just trying to help those who are trying to keep their models in one piece and have good performance without the "TIM THE TOOL MAN" (USA show of a self proclaim expert in power tools and likes nothing but raw POWER) attitude ;)

[guapoman2000]

P-51D........great news.....lets set it up like it has a Merlin Engine!!!

TURN UP YOUR SPEAKERS!!!!!! :D

http://www.angelfire.com/mi3/tomboshadows/Spitfire_Mk_14s_Fly_bys.mp3

http://www.angelfire.com/mi3/tomboshadows/P_51_Aerobatics_.mp3

[wolw]

P-51D........great news.....lets set it up like it has a Merlin Engine!!!

TURN UP YOUR SPEAKERS!!!!!! :D

http://www.angelfire.com/mi3/tomboshadows/Spitfire_Mk_14s_Fly_bys.mp3

http://www.angelfire.com/mi3/tomboshadows/P_51_Aerobatics_.mp3

No speaker on work computer :(

[Alex B]

Very impressed with that sound I can now imagine how people felt as these birds went by over their heads during WWII...jezzz...wish everybody had learnt the lesson :(

But if we could find the way to put this on a chip and make it go along the diff sounds as we pull the throttle stick...yihaaaa :D

Carlos I'm sure this bird will fly nicely on the AXI 5320/28...regarding the wing area if Graupner's details are wrong and is not 775 sq./inch it should be around 700 after all the messures I took last night...so it's a matter of flying it with either 32 to 39 or so sq./ft. wing loading... :eek:

Alex

[wolw]

Alex, I insist you get this (http://media.putfile.com/Sound-equipped-81inch-P-47-flight-1) :D

//Peter :D

[guapoman2000]

Alex, I insist you get this (http://media.putfile.com/Sound-equipped-81inch-P-47-flight-1) :D

//Peter :D

From a scale from 1 to 10 that takes an 11.5 in my book....the scale details, the sound system, the placement of ESC and batteries, and the flying is just super!

Great Video! :D Model

[Alex B]

Peter that would be great but then after this weight discussion we've had the guys would kill me :D :D :D

But just curious do you know who sells this ?

Alex ;)

[guapoman2000]

Peter that would be great but then after this weight discussion we've had the guys would kill me :D :D :D

But just curious do you know who sells this ?

Alex ;)

Alex,

Did you see the function of the FLAPS? Your model even though a bit on the heavy side (Assuming a lesser Wing Area) would come in like a pussy cat...down that runway with Flaps!!!! :eek: I would certainly consider the 17 X 10 propeller as you need thrust to keep a bit of thrust when using FLAPs.

If the AMP draw is just a little too much for Motor/ESC then, I would consider a 16 incher! ;)