Beretta

[Phil Winks]

It looks like Foamie Dave has a real treat in store for us if the photo's of his latest creation are anything to go by. I think I'd best make me an eze fan and get some jet training in. any Idea when it will appear in the mag? anyone

[David Ashby - Moderator]

June (next) issue Phil  

[Foamie Dave]

Hi Phil, besides being quite aerobatic, its designed as EDF trainer so its not tricky to fly if youve a little  aileron experience (big flying surfaces so its nice and stable) and it'll happily cruise on low throttle till you get the Jet Jockey thumbs warmed up

 

Heres a sneak peak video of the photoshoot (howling gale and grey clouds as usual..one of these days we'll get blue sky, fluffy clouds and a gentle breeze)

 

The chap you hear in the background is RCM&E ace snapper  Alex " A bit lower and crank the wing over for the camera" Whittaker...

 

http://www.youtube.com/watch?v=_Elq2-ha7wo 

Edited By Foamie Dave on 27/04/2009 11:43:07

[Phil Winks]

That looks sweet Dave it appears to have borrowed a little in the fuselage shape from the hawk. (thats a good thing ) not sure what the wings remind me off perhaps a meteor either way very sweet looking in the air. and I've found some epp sheeting so come on the june issue

[Foamie Dave]

Cheers Phil,

 

I can see why nearly everyone mentions the Hawk resemblance but the original side profile was based loosely on an Aero Vodochody L-39    (ill try and find my original paper template piccy), but when I fitted the bigger canopy if definately started to look more Hawkish from the side

 

Its also got a bit of  ViperJet up front (stubby nose to fit the lipo) and the wings are "old school" Grumman Panther-ish ..bags of  area and distinctive tip tanks, which makes for a really stable flyer. 

 

As you can hear in  the video it was a real howler of a day but it coped really well in the gust to say its only running on 3 cell (11volts)... although I reckon its still a bit fast for Tescos carpark at dinner hour

 

 

[Phil Winks]

What size/kv motor have you got in that 70mm df and what size lipo I'm assuming its full house controls will we need hi-torque servos anywhere. oh and just had a glance at some of what I believe are your other U-tube videos some smashing stuff really

[Foamie Dave]

The motor is a HET 2w on 3 cells  (or 2W-20 if you plan on using 4 cells) so its around 4500kv.  Its fitted in a Wemotec Minifan  so its quite a lightweight setup and balances perfectly with a 3000mah lipo. 

 

EDF's tend to draw quite a high current so you'll need a high "c" rated lipo to provide the juice (about 50amps ). 

 

I originally had Hitec HS 55s on the aileons but swopped these for bigger 65mgs after the intial first couple of flights which made it much more reponsive (and generally much nicer)  to fly. Rudder and elevator servos are 65MGs and again I wouldnt be tempted to go with anything with less torque.

 

Glad you liked  the vids mate,  as well filming my planes for the magazine,  Ill hopefully getting a few more snippets from around the shows this year . I think Weston Park was my favourite from last summer, its on  YouTube or a much better quality version here   http://www.vimeo.com/1246313  . Ill have to see if I can borrow a press pass for this year ..and dig out a zoom lens for the old camcorder 

[Foamie Dave]

Managed to dig out the original paper template along with prototype thrust tube (made from a coke bottle) and EDF unit to get the scale and proportions correct.  

 

Took exactly 3 months on and off  from the first doodles to the finished plane

[Phil Winks]

Thats still pretty quick in my book Dave I'm approaching the build stage of an own design inspired by some one in the mag who used the depron from under a pizza to make the wings and thats taken at least a month I reckon, and she is tiny (466mm span) should be fun once built though. Its suprising how much wing area you can get out of two 10" circles on a biplane. no less than 99037 mm2 so hopefully wing loading will be very light just got to write up the build seq and who knows maybe if its good enough David will take it for a freebie

Edited By Phil Winks on 28/04/2009 08:34:07

[Foamie Dave]

Doing your bit for recycling,  having a take away and building an aero at the same time ..cant beat a bit of multitasking and saving the environment  eh Phil

[Phil Winks]

to right Dave  actually its turning into a bit of a full on project so far I've got it down to about £5 to build the airframe what with replacing carbon rods with bamboo kebab skewers. and sourcing depron from pizza and other packaging. The name will have to reflect the design brief I thought "Cheapskate" but with a takeaway theme starting to occur maybe another will spring to mind eh

[RonSpencerUK]

Hi Dave

I really enjoyed making, and flying, your Tiger Moth, in fact it was my very first build. So I've got to have a go at the Beretta.

Can you tell me wher you got the EPP from?

I've done internet searches but can only find the low density stuff and 8 or 10mm but not 9mm.

Whats going to be next?? 

[Erfolg]

Having built your Ballerana, which I still have not got around to flying. What with stripping the gears on one wing of my Weisskannichen 2, then immediatly spinning my Holzflugel in, now needing a new body.

 

It seems that this Barreta could quite possibly get in the way, of my repairs. Im am sure that the constuctional methods will be of considerable interest to me. Looking at the flooring tiles i guess it is about either 700mm (2*300)? or a lot bigger at 1.2m

 

Anway, I will be very interested to examine the plan.

 

Erfolg

[Foamie Dave]

Cheers  Ron,

 

The EPP I used was the last of  Sloflys old stock when Steve shut up shop. I bought a boxful and shipped it from the States and its lasted me the best part of  3 or 4 years.

 

If you can only find 8 or 10mm either will be fine,  just  tweak the plans to take into consideration the changes in thickness in material. Again, using low density material will also be ok, just remember not to scrimp on the carbon reinforcement especially on the tail area or you  might end up with flexy tail surfaces, and stick carbon on the trailing edges of the ailerons to beef things up a little.

 

The gallery has a few build pictures we couldnt fit in the mag which shows how it goes together . Gallery Pics Here

 

Hi Erfolg,

 

I think this mag is due out any day so I dont think ill be giving the game away to give the dimensions.  Its 40" span by 40" length give or take an inch (theyre 15" floor  tiles and 16" Cassutt racer  ) .

Again the gallery pics probably give a better indication of how it goes together, but the construction is very similar to the big Edge 540 that featured in the xmas issue.

 

 

Whats gong to be next ....mmmm ..Ive got 2 or 3 ideas on the board (or on my CAD)  but ill make sure they fit together and  fly first , think its going to be a busy summer !!

 

 

Edited By Foamie Dave on 06/05/2009 23:26:04

[Erfolg]

What may be of passing interest, is that a design study by Messerschmitt P1112, also had the jet engine, buried in the tail with surface type air-intakes at the rear of the body. Although not totally circumfential, the intakes are substantial, partricularly for an aircraft from that era.

 

The wings though are very different, being swept. Although low aspect ratio, are proporitionaly large in area.

 

Your design, or principles, may make a facsimilie possible, it never really exsisted anyway. Not even making a mock up.

 

Erfolg

[Phil Winks]

Hiya Ron for epp supplies you should give "flying wings" a call they sell most densities and thicknesses or they did   

[RonSpencerUK]

Cheers Phil.

However, I've costed out the bits for the Beretta and it comes to £430.  Too rich for me at this time.

However, I've found an EDF/depron Hawker Hunter in a sister mag, costed it out at £120 so I'll have a go at that.

Good luck to all with the Beretta.

[Erfolg]

I guess the expensive bit is the Motor.

 

It is almost certainly to late, for inclusion in the magazine, but perhaps Dave can, identify the main parameters that matter for the fan motor combination, in his build thread that will follow.

 

With reard to speed controller, I would guess any suitably rated budget will do, as fine motor control is not necessary for EDFs?

 

I cannot see servos braking the bank as there are so many.

 

Even Lipos, with high C rating seem to be available from many sources at low (relatively) cost, these days, just not the main magazine advertisers, that are the live blood of the magazine (pity that).

 

What are your thoughts David? As you will have a far better understanding and knowledge than me.

 

Erfolg

[RonSpencerUK]

Hi Erflog

Yes, the suggested power setup comes out at over £200. The servos (HS65MG) are £20 a pop and you need four of them = £80 right there. 

You can no doubt make do with much cheaper items, but wouldn't that defeat the object of making a well performing, sharp flying model?

I'd be interested to know the minimum cost you can get away with though. 

[Foamie Dave]

Hi Fellas,

 

I used a HET 2w motor (£40), Wemotec minifan (£30), Wemotec Thrust tube (£10) or make your own (£0)  Turnigy 60amp esc (£30), 65MG servos (4x £20)..so its about £190 plus reciever and lipos.

 

EDF's take quite a bit of current compared to an equivalent "conventional" propped motor  so you'll need lipos capable of around 50 amp burst, again prices vary but expect £20 +per battery (Zippy / Flightmax / Rhino - Hobby City)  or more for branded ( Overlander / Flightpower/ etc ) batteries...again , pays ya money takes ya choice.   A couple of lipos should see you through the afternoon if you have a charger at the field ..I very rarely fly just one model on a day out so a 30 minute wait between flights soon passes.

 

With a bit of shopping I reckon you could get a decent similar setup (try BRC Hobbies, Modellhaus or Puffin)  for a few pounds less. If you really need to cut back , budget fans are available but again try a specialist like BRC for some recommendations ( cheap dosnt always mean nasty but Id avoid ebay fans like the plague) . They may be down a little on performance but anything fairly efficient around 400w + should drag it around the sky just fine, or use 4cells for a bit more ooomh. ( the video is on 3 cells and mostly on half throttle except for a few flat out passes ..and it was very windy)

Hope this helps

[Foamie Dave]

continued fom my previous post on the other page (it was getting a bit long) .. an update on EPP suppliers

 

Like Phil has just mentioned (cheers Phil) , Flying Wings stock nice quality foam

 

I think Robotbirds still do it  although you might have to phone for upto the minute details on what is in stock although the density and thickness varied slightly  from batch to batch last time I ordered. It was definately worth looking at, just try and grade / batch the sheets beforehand so matched parts use same thickness  of foam

http://www.epp-versand.de/ (Germany)  has stock . This EPP looks to be hot wire cut (thin skin on ths surface)  but very good quality. Postage isnt too bad if you buy a dozen or so sheets. They also do depron and other some nice bits and pieces. The foam is on  this page

 

The nicest material Ive used recently is from RCFoam  in the US ( Ive had a few sheets delivered this week) but unfortunately shipping is very expensive and customs / parcelforce also take a huge cut . Look to double the cost of your order to cover shipping and customs. ..ouch

Edited By Foamie Dave on 08/05/2009 08:54:25

[Erfolg]

I think you do need to be realistic with regard the cost of the EDF motor.. Relative to an outrunner, conventonal armature will always (he says hesitantly) be more expensive to make. They firstly need to windings that are able to withstand high revs, secondly the bearing arrangements need to withstand the high speed and finally the current drawn is so much higher and cooling so much more difficult to acheive.

 

With regard to the fan unit, many of these are relatively cheap, considering the forces experienced and speed achieved. The criteria here must be, is it efficient and work. To me a very grey area. I guess others will have some idea. Why is it that Schrueble (if correctly spelt) seem that more efficient than many others.

 

I still believe there are many servos and batteries that can be obtained at modest cost.

 

Although I am sure some will come up with a lowish cost, good performance fan and motor unit. Just tell us about it!

 

 

Erfolg 

 

[Chris Salomon]

With regard to servos, do we really need to lash out £20 each?  How about something like this I know they're not metal geared but they have ample torque and only £14.99 for four!

 

Oh, and I have NEVER even considered building a foamy and certainly not a ducted fan..............until now!  What a sweet one this is, nice one Dave!

[Foamie Dave]

Erfolg, I totally agree with you mate 

 

As a ballpark figure the  EDF motor and fan unit must be spinning around four times faster than a conventional  prop driven setup so taking a shortcut in this area is a recipe for disaster. If youve ever seen a fan "let go" you'll know what I mean. I went for the Wemotec and HET setup as they have an impecable track record and only cost a fraction more than an inefficient  budget setup.

 

BTW I'd love to fit a Schubeler in it ..but I need to pay for the heating AND food this month

 

Hi Chris, Cheers for the compliments, much appreciated .

 

Servos are always going to be a subjective point, but having originally flown the Berretta on HS 55's (and the controls went a bit vague at full steam) I'm all for  putting in something I know wont let me down.  That aside, those servos certainly look to have a  very impressive spec, but without knowing anyone that has tried them unfortunately the only way to find out is to give them a go.....or better still get a buddy to install some and see how he gets on ..from a safe distance

 

If you do get any i would seriously be intersted on how they perform ..I have another couple of projects they might just fit niceley into

 

 

Edited By Foamie Dave on 08/05/2009 20:03:41

[Chris Salomon]

Dave,

 

I have got some of the BRC servos that I am putting into a Nijhuis Mosquito but are, as yet, un-tried.  I suppose I should finish that first before getting tempted to build the Baretta!