Ripmax Spitfire EP

[Tim Mackey]

Now this is really spooky - cos I was only thinking earlier this evening that I may well try 4 x A123 cells !

[Chris Bott - Moderator]

The 1400 Axi is now in a P51 funfighter with 4S A123 and a cocktail stick of a prop. It goes well, but I'm not sure the motor will last

[Mark R]

Hi all, is anyone doing a build blog on how to instal retracts and what retracts they use and how good they are etc etc

[martyn sharp]

 Hi Mark I will probley do a build blog on fiting retracts but, I,m moveing model Rooms so all on hold for a bit but im useing  these but i will add to the thread  when I start.
 

 Martyn. 

[Mark R]

Hi martyn, cheers for that....look forward to the build blog

[Mark R]

Just a thought, weight issues, we all like to keep em light etc...but with the change in engines and batteries, how much are people putting up front in the way of lead ballast (or balance)?

 

cheers Mark

Edited By Mark Rowse on 06/06/2010 17:25:16

[Kelly]

 

Well, I have a commercial spinner in place of the Ripmax eggshell, plus scale exhaust stacks(carved balsa) and 20g of lead in the nose.

 

It has a flying weight of 3lb3oz with a 3300 3s 11.1v flightpower lipo.

 

Nice reserve of power means a scale looking speed at 40-50% throttle and the  power to pull it through large loops etc .

 

Kelvin 

[Tim Mackey]

Mine uses a lightweight outrunner, metal spinner and folding carbon blades, and with a 2300 3s lipo and 40A ESC in the main battery tray area, weighs in at 2.5 lbs exactly and has no ballast anywhere....front or back.

The battery sits towards the rear of the tray - I can photo it if you want.

Not hugely powerful, but perfectly scale like, and loops are nice and big, with around 7 minutes duration also.

I like to keep it light and lower the wing loading for slower landings - plus - I slope it too - so light is best for those somewhat rough terrain landings

Edited By Timbo - Administrator on 08/06/2010 00:41:49

[Kelly]

Thought that was a tad heavy, re-weighed tonight

 

2lb 14oz

 

Kelvin

[Tim Mackey]

You fibber LOL

[Kelly]

 My excuse

Aldi scales .

[Tim Mackey]

Mine are Lidl 

[Mark R]

Hi Timbo, not weighed mine yet......no lidl or aldi near me lol...got a Spar or will that be too high class lol

Balancing it with an axi 2826/10  3s 2500 lipo and its bum end heavy .......even with battery pushed right forward, started to put weight up front, got to about 50g or so and still drooped at bum.  Balancing upside down, with markers about 75mm from leading edge.  Now this model is ermm somewhat old, was bought 4 years ago, built and ermm left laying around, that likely to have caused problems? Not got wet, spends its days in house away from sun and damp.  Used epoxy on tail end when i built it, not massive amounts tho...at a loss as to why its sooo tail end heavy, i know it was designed for a brushed motor and nicad batts, but the axi is 180g plus a turnigy 3s 2500 batt.  Dont really wanna put loads of lead up front, like my planes a lil nose heavy, but front end looks fragile (even after regluing).  Any ideas would be gratefully received

[Jeremy Butler]

Mine weighs in at 2lb 8oz with a Turnigy 3542, Flightmax 2200mAh 3s, 2 aileron servos and I have also fitted a flycam eco just behind the canopy in the side of the fuselage. Balances on 70mm from LE with 10g of weight added on the motor mount which I added after fitting the flycam. 

[Tim Mackey]

Hmmm - Jeremys sounds very much like mine then, and you Mark, are the odd one out IYSWIM

First picture shows a1/12" balsa nose ring I made when I had a different motor  fitted before - the shaft was too short.

I left it in place when I fitted the current motor ( keda1000 kv ) which weighs 3.5 oz

 

This next picture  just about reveals it after finishing.

I sprayed the cowl and dirtied up the exhaust stacks a bit

 

Next is the battery position - the black lines indicate the approx position that a 2300 mah tipple 3s fits at - in order to balance correctly.

As you can see it is nowhere near pushed right in the frontal area.

 

Heres the battery.... quite a lightweight really

 

Here she is sitting on the balancer

 

 

Weight is actually now 2lb 9oz ( she has put on 1oz ) due to the fibreglass and tape I added to the underside of the fuz to prevent scrathing on landing up the Orme )

 

 

The balance point is EXACTLY 75mm from the wing leading edge directly infront of the COG balan ce mark points shown below. I balance her on the rearward line of the "box"

as shown here....

 

I doubt this little lady adds any more than a couple of grams - even with her ciggy Wifey carved him out of pink foam   ( its her model really )

I hate an empty cockpit

 

Note the bullet hole which just misssed her right shoulder...damn 109s

 

Incidentally...somewhat off topic, but this picture also shows the now infamous spektrum AR500 receiver poking up behind her head, with the one fixed aerial orientated across the fus. The extended aerial section can be just seen in the earlier photo of it on the balancer...the active aerial section just poking vertically out from the top decking around about where the full size radio aerial would have been. As with all my AR500s, absolutely fine, and the range was tested big style on Sunday PSSA meeting with the model being flown at great distances, almost OOS over the Irish sea.

Hope some of this helps.

Edited By Timbo - Administrator on 08/06/2010 11:24:05

[Jeremy Butler]

Here are some shots of my set up and the flycam eco in position. The door is not quite finshed yet.

[Mark R]

Hey folks, many thanks to Timbo and Jeremy for their pics......given me something to think about.

Was thinking Timbo,if yours or should a say the wifes is ermm hers, shouldnt it be a stripped down one with no radio in it etc so its like an authentic one from the second world war, when young lasses would fly them from the 'shop' to the airfields,now thats a job i wouldnt want, untried n tested, but its ok for the little woman to fly

Like the camera idea Jeremy

 

Well i am going to see whats what with mine......head scratching time.

 

 

cheers all

Mark

[Dave Bran]

No doubt there's some very interesting posts in this thread!!

 

I'm really puzzled though how some seem to be so much heavier/lighter than others, and to be completely honest, I'm beginning to get a bit wary of some of the data........not having a go here guys, but the measuring devices used just MAY not be that accurate?

 

OK, here's my data, for what it's worth. Guns out, ready to shoot??? 

 

Mine is built completely stock as regards airframe, and was built as light as possible. The only addition is a balsa and vacuum formed Pilot and the only Mod was dictated by the rear mount brushless, shortening and strengthening the mount.

 

I initially felt I would be happy with a "PSS with power assist" type of installation, (or that's what I WAS aiming for, see later!!!).

 

Relative to many here, my chosen motor is very puny in terms of size, it's only a 2814, but I'd had it to hand for a couple of years or more, it was burning a hole in my motor box, and I was spending my money elsewhere at the time!!!:-

 

http://www.giantcod.co.uk/a28146-1410kv-brushless-outrunner-motor-p-402433.html

 

It's stated as 100g, sorry I didn't weigh it personally, so that's Cod's data.

 

It's fitted with folding 9x5 blades and a 50mm spinner with tip vent hole (scale buffs look away now)

 

 Ready for flight (?) the plane weighs in at 1185g, which is 2.6 lb.  (after a struggle, I no longer "do" imperial). With the battery front right forward against the revised motor mount plate (with formers opened out slightly to allow), I only needed 50g of lead (included above) on the motor mount cheeks to balance marginally forward of the rec'd 70mm point.

 

I'm using 2300mAh 3S 30-40C Tipples, and fitted a 40A Hobby Wing ESC, which I have found to perform well at all throttle settings and stand abuse.

 

I have just completed the build, it's not yet flown. 

 

Data from my DPC, plane held static, for the overall test, is:-

 
Battery Efficiency: 88%

Max Current: 47.30 A
Avg Current: 17.01 A

Max Voltage: 12.52 V
Avg Voltage: 11.71 V
Min Voltage: 10.80 V

Max Power: 523.57 W

Avg Power: 192.82 W

 

 

Half throttle data:-

 
Battery Efficiency: 99%

Max Current: 24.26 A
Avg Current: 24.11 A

Max Voltage: 11.33 V
Avg Voltage: 11.22 V
Min Voltage: 11.20 V

 

Max Power: 271.76 W

Avg Power: 270.26 W

 

I have in the past compared the DPC against other data recorders and it seems accurate enough.

 

I'm not too concerned at the 47A top end, as it will unwind and reduce in flight and I have no intention of flying it like a pylon racer anyway.

 

After a static run using flight type variable settings the motor, ESC and battery were all just off cold.

 

Thrust seems "adequate"..........................(in a Rolls Royce sense) 

If it survives long enough I'll fly the DPC in it and get true flight data.

 

 

 

 

 

 

 

 

 

 

 

 

[Tim Mackey]

Not sure what you mean about the data Dave - your model is pretty much identical to mine and at least one other here at around 2 1/2 pounds. OK so you balance 5 mm further forward than mine....buts thats no biggy and just reflects the individual preferences I guess

PS just rechecked the weights on both sets of scales in the house. Both "digital kitchen" type units, and both read indentical figures, so I am pretty happy that mine is correct

....if only MY weight was 

Edited By Timbo - Administrator on 08/06/2010 19:18:01

[Chris Bott - Moderator]

I've just looked back over a couple of pages and can't find much in the way of varying weights. Except for a miss weigh which has been re-weighed. Some people will have heavier batteries, servos, receivers, esc's and motors. So there will be some variation.

[Jeremy Butler]

Just rechecked my models weight on another set of digital scales and get exactly the same reading.

 

[leccyflyer]

There's so much variation in the motors, batteries, receivers, ESCs, propellors and spinners used that it is inevitable that there will be variation in the weight.

 

Now, if only Ripmax could be persuaded to replace the monstrosity of a cowl with the much nice one that the otherwise close to identical model that is supplied with the widely available in the Far East, which also has a retract option.

 

Edited By leccyflyer on 09/06/2010 12:10:17

Edited By leccyflyer on 09/06/2010 12:12:25

[Tim Mackey]

I actully prefer the Ripmax one...no accounting for taste eh!

Incidentally, your avatar is uncannily like Gemma Janes'

[leccyflyer]

Though it's not my model  (we don't have Kookaburras hereabouts) the HA one has all the disadvantages of a non-silvery colour scheme, retracts and a cowl that doesn't look like it's been liberated from a P-40. The main construction looks to be very similar to the Rippers Spitfire though and reports of the flying characteristics are equally positive..

 

The avatar is  Big Les (or actually a smaller version of him) - a teddy pilot sold at airshows all over the country. If it's the same as some other poster's then I'll happily change it.

[ken anderson.]

today my old ripmax spit appeared at the cliff's to be flown as a glider....and what a glider it is----holding it's own with no nasty vice's...and the landing was amazing.......once over the spot it just sat there-quite happy....no stall/wing drop's -nowt........it just lost height and sat down.........(20 mph wind)....

 

    ken anderson....ne 1....