Question about Hanno's Magic
 

Hi all,

I am studying the RCME plans for the Hanno Prettner’s Magic.
There is a special thing that worried me: the refrigeration of the engine.
In the plans, the question remains unclear. (For the turtle deck and the tuned pipe it is easy.)
In some photos of the first Magics, it seems that they don’t have the side gills that appear in the MK and other fiberglass kits of Magic. In these “first” Magics, only the frontal intake hole and the big down hole in the engine cowl are visible.
But, only with this system, frontal intake and down exhaust across engine, seems to me very poor.
Despite that the addition of the side gills, extended to the rear/down of the engine cowl, can make the question more reliable, I suspect that Hanno don’t work with this gills, but his Magic’s engines work with good refrigeration.
Anyone know any about this?

Thank everybody in advance.

John

RE: Question about Hanno's Magic
 

Engine air was ducted down the pipe tunnel, exits at the two fairings just in front of the fin.
Evan, WB #12.

RE: Question about Hanno's Magic
 

John,

Have You read this?
http://www.trentonrcflyers.com/patte...cles/magic.pdf

/Bo

RE: Question about Hanno's Magic
 

John,

I'm not sure I follow what your concern is but maybe the photo below might clarify the cooling.

The engine installation is typical of inverted pattern engines except the pipe runs atop instead of under the wing as with other designs (e.g., Aurora). As you can see the frontal opening extends below the spinner to allow air into the carb as well as over the cylinder. The cowl is also open underneath where the cylinder exits exhausting the air. Depending on whether the fuse is glass or wood, the configuration changes slightly but the concept is the same.

David.

RE: Question about Hanno's Magic
 

There are two cooling paths. For the engine, air enters via a slot in the lower front of the cowl as normal and exits via a series of holes in the lower rear cowl. For the pipe, air enters a slot at the front of the canopy and exits via two ducts at the rear of the upper deck.

Ray

RE: Question about Hanno's Magic
 

Doxillas reply shows a different version of a magic (with side exhaust) to the RCM&E version which uses a rear exhaust engine as per Hanno Prettner.

I planned to have the holes as per Rays pics but had to have the front of the cylinder head protruding 1/8" through the cowl as my webra 61 long stroke engine wouldnt fit otherwise. I chose to leave the area behind open for cooling though this isnt visible from the side and it keeps its sleek look.

The exhaust header goes through the first bulkhead via a large hole then up into the top deck . This area is also open into the retract bay. There should be a door on the front wheel but mine was damaged when the retract didnt lock so I left it off (aiding cooling airflow).

The plans also say you should have a slot at the bottom of the canopy to let air in but I didnt bother, assuming I could add this later if needed. Vents to the rear of the turtledeck would draw a reasonable airflow through past the tuned pipe as the plane flies.

http://i529.photobucket.com/albums/d...r/CIMG2119.jpg
http://i529.photobucket.com/albums/d...r/CIMG3047.jpg
http://i529.photobucket.com/albums/d...r/CIMG2110.jpg

RE: Question about Hanno's Magic
 

Thank you all, for your helpfully replies.

Very interesting and curious the reading proposed by bem. In it, Hanno says that his top turtle deck is made with conventional balsa structure.[X(]
Also, Hanno states his no need for engine pump, very curious.
I think that the "multi little hole" solution (RFJ) and the "only a great hole" solution (dave), will be used according to the exact size of the engine used.

Finally, dave, what is the use of that silicone tubing that runs with the pipe and exhaust?

RE: Question about Hanno's Magic
 

Hiya

I use a pumped webra so the tank is open to the air. So fuel cant drain out no matter what attitude, I routed the vent pipe from the front /top of the tank to behind and below the tank, out the bottom of fus behind the wing. Following the tuned pipe seemed a neat way. I fill the tank with a "quick filler" valve located in the top of cowl.

I was a bit narked to say the least when I found the engine wouldnt fit in the cowl. As I had the cowl vac formed from my own pattern I only had myself to blame. Making a new plug/cowl is a "longer term" plan but to be honest I think it worked out well as it was. Vortex Vacforms (Leicester, UK) has the pattern and should be able to supply identical cowls very cheaply. A standard stroke webra 61 "should" fit but the LS webra was a bit too tall.

My turtle deck is made from a lite ply base with a hole to clear the pipe. I used 1/4" square strips along the length, five 1/4" balsa formers and 1/64 ply skin glued to the 1/4", glass clothed for strength & pop bottle canopy. Vents are thin ally tube cut at an angle.

Cheers
Dave

RE: Question about Hanno's Magic
 

Dears,

The thread is a bit old but I'll give it a try:

I am finishing my scratch built Magic60 from the RCME plans with some mix in from the MK plans when it comes to engine installation.

My question is - what engine should I use? I have a whole set of rear exhaust Webras: Standard stroke, long stroke (black and red head) with and without pump and with dynamix or TN carbs.

The standard stroke would be higher revs (up to 17k rpm), the long stroke black head less so (up to 13k rpm) and the read head even less but with better cooling requiring a larger cowl opening...

Any opinions?
       /Magnus

RE: Question about Hanno's Magic
 

fast_mag,

unfortunatelly, our little airfield, despite our care, show a roughly grass almost all the time, and my Hanno's projects remain in his first stages because it couldn't run well in this surface (low ground clearance for the propeller, and bad field for a wing's based landing gear).

Despite this, in my study of the plane, I have collected the impression that the Magic is a ballistic aerobatic plane, and thus it will need speed.

With a short stroke engine, I think that there is no problem. Also, best with pump if the system works with more reliability.
Despite this, a long stroke give you the chance of use for a more long diameter propeller, and thus change some speed for traction.
It will work better for the aerobatics, but it gives to you some problems with the big diameter of the propeller, the larger landing gear needed and the greater space required in order to retract it.

If I have your luck in having various engines, I will try first the best and reliable engine system for a 12x6-8 and see it.
Then, don't worry about cooling openings. A full open in the under part of the cowl is almost required and wellcome in the warm days. A sloping deflector in the low part of the firewall also helps, as dave show in the pictures.

Finally, my congratulations to you for to be an scratch builder, and moreover for to build the Magic; good luck with it!.

RE: Question about Hanno's Magic
 

Yes the Magic is a ballistic plane, I think Hanno Prettner reduced airfoil thickness little bit compared to the Curare if my memory serves right....
He flew it with a short stroke Super Tigre rear exhaust, and of course the variable pitch prop.

If you like to stay close to the original, I would put in the Webra 61 Speed rear exhaust with Dynamix carb and pump. For less noise and adrenalin, take the longstroke version...

Good luck!

RE: Question about Hanno's Magic
 

Thanks!

My Curare60 from way back in the dark ages runs with its original Webra speed 61 dynamix without pump and the adrenaline is always present. I guess I'll try that config first...

Cheers,
/Magnus

RE: Question about Hanno's Magic
 

WOW nice Magic!!! Rob.