Author Topic: EL take-apart Firecracker - Mods done to old fuselage (Read 1368 times)

Bruce Hoffmann · « **on:** January 27, 2011, 09:33:26 PM »

I've just finished the 'mods' on my 'take-apart ' Firecracker - it originally started its life about 3 - 4 years ago with a Saito .56 four stroke in it, didn't fly particularly well so it was just taking up space in my garage until about this time last year when I decided to do a quick build on a new fuselage and electrify it. The end result was that I had a really well performing model but I was never completely happy with the paint job as it was just an experiment at the time and I didn't put much work into the finish. Also, I didn't like the 'red' fuselage.. didn't think it went well with the original wings that were mainly yellow and blue.

So a few weeks ago I decided to cut it all back and put some 'cheek' cowl inlets up front, change some of the exit air vents and just generally give it a 'make over'. I think it looks way better now than it did in its first electric state however hopefully tomorrow is the maiden flight with its new look so I guess I'll find out then regarding its performance.. Overall the 'mods' put on about 2 oz - so now it weighs in at 64 oz with the heavier 3700 Rhino battery, although with the nano-tech 3000mah's it will be back down to just over 62oz.
I've attached here a few photos depicting the original Saito powered version, the 'red' EL version and now the latest with the cheek cowling. You may be able to see in the 'red' version there were a couple of air vents just forward of the l/e of the wing on the fuselage; I've now partially hidden these with a plastic spoon (cut into about 3/4 length) which adds a nicer look to the exhausts in comparison to how they were previously.

PJ Rowland · « **Reply #1 on:** January 27, 2011, 10:39:52 PM »

Red and Blue will never do..

Blue and green should never been seen.

Certainly looks better with the yellow Fuse. -

Dennis Adamisin · « **Reply #2 on:** January 28, 2011, 04:26:23 AM »

I thought the Red fuse was a nice change but now seeing the yellow fuse - it just looks GREAT!

With the 2 cheeks and a chin scoop you have a lot of air coming in - do you find you need that? Can you show some pix of the air outlet areas?

jim gilmore · « **Reply #3 on:** January 28, 2011, 01:25:21 PM »

Looks good. My only complaint is that 1 120X160 photo image is nothing more than a postage stamp. I use a netbook.
Wish everybody would use at least 800X600 or so.

Bruce Hoffmann · « **Reply #4 on:** January 28, 2011, 11:29:11 PM »

[quote
With the 2 cheeks and a chin scoop you have a lot of air coming in - do you find you need that? Can you show some pix of the air outlet areas?
[/quote]

In my other model - another Firecracker with a Plettenberg 2510 motor I was finding taht the temps were getting quite high - I increased the air outlets on it but they still often registered in the high 69 deg. (celcius) range. When I was re-doing the fuselage on this model I thought I'd increase both the inlet and outlet vents, also hoped that the cheek cowling may induce a small amount more drag which could inhibit the tendency to 'wind-up' in windy conditions.

This model currently has the Arrowind 2832 motor with the Phoenix Ice 50 ESC (same ESC as the other Firecracker), I managed a few flights with it today and whilst the ambient temperatures weren't 'hot' they were still in the mid to high 20's (C) - I checked the temps later and found that the ESC had only reached 46 deg (C) - so not sure at this stage whether the Arrowind plays a part in keeping the ESC cooler or the extra venting I've created. In the next few weeks I'll try the Plettenberg in it and then I'll know for sure..

The good news is that the model flew like a dream! Couldn't hope for better. I brought the RPM down to 9000 and using an APC 13 x 4.5" prop with 68.5ft lines (centre to centre) the model easily flew at about 5.7 s/lap - plenty of line tension everywhere and nice sharp corners on the manouvres that need them. I'm a very happy!

I've disassembled it for tomorrow (I'm taking a couple of people out in my car with their models too so needed the extra space) and taken a few more pictures on a lower resolution showing the air vents and 'take apart' design.. I had trouble posting the previous photos - that's why the size is so small, hopefully these will improve things!

Dennis Adamisin · « **Reply #5 on:** January 29, 2011, 07:45:50 AM »

Thanks for the new pix Bruce!

I like your system - simple and (based on your results) very effective! I am working on a new bird, mostly laying out the cooling details now.

It will be interesting when you run the Pletty in the new set-up, the Pletty has a cooling fan too right? . My Arrowinds all run real cool but I do not know why the Arrowind is inherently cooler than the Pletty. Arrowind uses a contemporary 14 pole design, the Pletty is 10 pole, but not sure that translates into meaningful heat. Back when I ran the 10-pole Brodak "red" motors from the original Super Clown they ran pretty cool as long as there was air coming in. The Pletty's internal bearing probably restricts cooling airflow inside the shell but I thought that was what the fan was for(?)

The Arrowind is one of the largest motors out there in the 30mm dia class (Scorpion also has a 3032); longer motors = more power, and more power = less heat when doing the given amount of work, none of that is too surprising. Do you know the Commutator dia and magnet length on the Pletty? That would let you compare the motor sizes more directly, possibly leading you to a comparable Pletty?

I am also surprised at the 9000 RPM on 68.5' lines. The FC is obviously not very draggy and that's more evidence that the motor does not have to work very hard.

jim gilmore · « **Reply #6 on:** January 29, 2011, 10:20:10 PM »

Thank you very much for the larger photos. I appreciate being able to open them and see your work. Sorry if I sounded badly for my post.
But THANKS .

Bruce Hoffmann · « **Reply #7 on:** January 30, 2011, 12:46:00 AM »

Had another fly of the model today - quite hot (over 30 deg c) and variable winds with thermals and alot of turbulence from trees nearby. Had my girlfriend video the flight but unfortunately she had some 'issues' with her camera for the first few seconds and all you can see is topsy-turvy and her shorts! She finally gets it going on the 2nd of the 3 inside loops.. lots of noise in the background as I was flying at a 'model park' where there are 'ride on' trains, R/C cars, planes and boats.. however you can hear the sound of the EL model well enough and get to see what sort of speed it was doing.

Here is the link to the youtube video:

Re the Plettenberg - no I haven't a fan on mine but its not the motor getting hot so much as the ESC in that model.. thinking that perhaps because it has a slightly lower KV rating that the Arrowind (930 -v- 960) that the ESC has to work harder to allow more voltage through to the motor to obtain the same RPM as the Arrowind?

Also... no offence taken at all re the photos... I was having trouble uploading them and then resizing to allow me to put them on the site etc, I thought they were too small too but as I'd spent way too long at the time in 'edit' mode I gave up for a while.. Glad the new ones make them easier to see!

Warren Leadbeatter · « **Reply #8 on:** January 30, 2011, 04:40:33 AM »

Quote from: PJ Rowland on January 27, 2011, 10:39:52 PM

Blue and green should never been seen.

Except with a colour in between... (or so the saying goes)

Very nice Bruce. Too hot for flying today... I was at the beach all day, cooked a bbq lunch on the beach, then when I came home later I spent the evening in the spa!

I did fly some electric yesterday arvo though at Mannering Park, under tuition from Jeff Reeves and Grant Whiley.

Cheers

PJ Rowland · « **Reply #9 on:** January 30, 2011, 04:34:54 PM »

You boys are Soft..

We had 40.2 Yesterday and I played 9 Holes of golf then built for the rest of the day..

Russell Bond · « **Reply #10 on:** January 30, 2011, 04:55:08 PM »

Huh!.........46.5c yesterday and I worked in my hot tin shed (some of the day)....

Same today, cool change tomorrow....down to 34c....

Bruce Hoffmann · « **Reply #11 on:** January 30, 2011, 05:19:03 PM »

Well yesterday in the heat I 'ran' for an hour in a Free flight 'Scramble' event (before going to fly the EL Firecracker) - sweat dripping off.. drank loads of water... good thing I'd been doing a bit of jogging the past month - I still had difficulty in walking/bending over afterwards though... must be age catching up...

Now off to do my first bit part as an 'extra' in a locally produced film starring "Olivia Newton-John" - maybe I'll get lucky?

Russell Bond · « **Reply #12 on:** January 30, 2011, 05:21:14 PM »

There's a word for you Brucie......but I ain't saying it!!!!!

We're all mad!!!

BTW; Your plane looks so good now!!!

PJ Rowland · « **Reply #13 on:** January 30, 2011, 10:12:15 PM »

We breed em tough Down under .

Author Topic: EL take-apart Firecracker - Mods done to old fuselage (Read 1368 times)

Bruce Hoffmann

EL take-apart Firecracker - Mods done to old fuselage

PJ Rowland

Re: EL take-apart Firecracker - Mods done to old fuselage

Dennis Adamisin

Re: EL take-apart Firecracker - Mods done to old fuselage

jim gilmore

Re: EL take-apart Firecracker - Mods done to old fuselage

Bruce Hoffmann

Re: EL take-apart Firecracker - Mods done to old fuselage

Dennis Adamisin

Re: EL take-apart Firecracker - Mods done to old fuselage

jim gilmore

Re: EL take-apart Firecracker - Mods done to old fuselage

Bruce Hoffmann

Re: EL take-apart Firecracker - Mods done to old fuselage

Warren Leadbeatter

Re: EL take-apart Firecracker - Mods done to old fuselage

PJ Rowland

Re: EL take-apart Firecracker - Mods done to old fuselage

Russell Bond

Re: EL take-apart Firecracker - Mods done to old fuselage

Bruce Hoffmann

Re: EL take-apart Firecracker - Mods done to old fuselage

Russell Bond

Re: EL take-apart Firecracker - Mods done to old fuselage

PJ Rowland

Re: EL take-apart Firecracker - Mods done to old fuselage