Hanno Prettner Curare ARF


Photo by Karlheinz Gatschnig, www.http://gatschnig.at

I am doing a review of the new Hanno Prettner Curare ARF for our magazine, and since that magazine is in Norwegian, I’ll also post it here for a broader audience. The Model is produced by Modellsport Schweighofer in Austria. (It’s made in China exclusively for Schweighofer from their specifications). It will be available in two colors: Blue/orange and green/orange.


Me on the left, Hanno, and Conny Åquist in Klagenfurt with the new Curare ARF. Photo by Hanno Prettner Jr.

The new ARF is endorsed by Hanno himself, and he has been involved during development. It is based on the MK Curare 60 kit drawings, and modified for ARF construction, and also changed significantly in the nose section to accomodate electric power (It has a detachable cowl and canopy, and a battery tray). The same model can be powered either with glow or electric, parts are included for both.
Schweighofer have built and extensively tested at least three prototypes, and Hanno has flown both glow and electric versions. He has one himself, an electric one that he flies regularly. I have been fortunate enough to visit his field in Austria and testfly his model, and it flies great – it’s not like a 2 meter model, but surprisingly close. It is the ultimate sport and retro F3A model.

Note: I have a pre-production model, the shipment of production models (600 of them!) is coming soon.

Kit contents
The standard size ARF box holds no surprises. Wing halves, fuse, stab halves, rudder, etc, all nicely packaged. It’s when you start to look at the manual that you see how complete it is – there’s hardly any work left to be done by the builder! Noteable prefabricated things are wheel bays in the wings, servo mounts ready (even the covering is removed), every surface is pre-hinged (you just have to add thin CA), the canopy is cut, fitted and painted with the proper trim, the cowling is ready to mount (for electrics – you have to cut an opening for a glow engine), pushrod guides installed, firewall and tank area fully fuelproofed, firewall blind nuts installed -the list goes on. You’ll also notice the intricate trim scheme – it faithfully reproduces the paint scheme of Hannos original Curare in many colors and dozens of stripes and fancy trim. (He had both blue and green versions so both are “correct”). All hardware required to complete the model is included – as well as a tank, and mounts for both glow and electric motors.

The only thing required is a suitable undercarriage. No undercarriage, fixed or otherwise is in the box. Thankfully Schweighofer stocks a suitable electric retract kit of high quality. The model is retract-ready, so that you would have to modify it significantly to fit any fixed gear. The electric retract kit is is complete with a nice 3 – 1 cable, and extension cables are also supplied. Most pilots have an old set of retracts in their parts drawer. You can fit almost any type of mechanical or pneumatic retracts if you wish, and the common Supra mechanical retracts fit without modification.

The undercarriage legs have to be cut to length (specified in the manual). A Dremel disc cutter is prefect for this.

You do not have to file flat spots, as everything is held in place by double set screws.

I opted to build the glow powered version. It is designed around the O.S. .55 AX. You do not need to fit a tuned pipe, but I thought it was right to have one, both for the looks and for the extra power and low noise it provides. Schweighofer does not recommend the use of a bigger engine. The model is far lighter than the original and uses CAD-designed lightweight construction, so you could have CG problems if you fit a 60-size engine. The target weight is 3,1 kg for the glow version.

The build
The instruction manual starts with the joining of the wing. I opted to complete each wing half before joining. I found that easier, as each wing half is easier to handle. The retract simply slot in, just remember to add the extension chord first. When the aileron hinges are glued, servos hooked up, and the retracts are installed, then I joined the wing. The wing joiner is strong, light, and the fit is perfect.


The retract kit from Schweighofer as it is delivered.


Add a piece of heat shrink tube to secure the extension chord before installing the main gear


The main gear installed


I used a different approach for the ailerons than specified in the manual. While the supplied equipment will do the job adequately, I tend to stay away from plastic links so I used ball links that I had lying around. The supplied aileron and elevator horns are surprisingly good, not unlike MK horns, but through a force of habit (Old habits die hard!) I used my tried method of simply gluing in a 3 mm. threaded rod. I use this method on 2-meter models, and it holds up well. The Curare ailerons are not thick, so I beefed up the wood by saturating it with thin CA, before gluing in the rod with rubber-strengthened thick CA. I have previously used Epoxy, so we’ll see if this holds up. If it proves weak I can always substitute these for the supplied horns.


Joining the wings are uneventful – You just glue in the joiner, and then join it with 30 min. Epoxy. After that you add the two forward dowels and the plate shown in the picture. That usually completes the wing on a normal ARF, but the Curare has flaps, and we’ll tackle them next!

Click here for part two, when we install the flaps and nose gear.

13 Comments

  1. Chuck
    Posted July 31, 2013 at 16:22 | Permalink

    Hi

    I read your Curare article. I am interested in selling the kits in the US and Japan. I have a partner hobby shop
    with the largest capacity in Japan. I tried to call and email schweighofer many times, but they dont respond. Is there any special email or phone number that you can share with me? I am in Los Angeles and a F3A flyer.

    Thank you.

    Chuck

  2. Charles
    Posted October 30, 2013 at 22:42 | Permalink

    Thanks for your great review. I have just got my new kit.
    I do not find a measurement for the dihedral, which I would like to check before gluing the wings together.
    Do you know what is should be?

  3. Jon Gunnar Wold
    Posted October 31, 2013 at 07:54 | Permalink

    If you’re fitting a glow engine, the built-in dihedral is fine, i.e. just fit the wings together and it automatically aligns. Mine fit extremely well with no play.

    If you’re fitting an electric motor you must add a little dihedral because the lateral CG will be higher -there is no heavy pipe underneath and the heavy battery sits above the fuselage centreline. Leave a gap of about 1,5 mm in the bottom of the wing joint, fill it with a balsa or plywood shim.

  4. Jon Gunnar Wold
    Posted October 31, 2013 at 07:56 | Permalink

    …I said add dihedral but meant increase dihedral, obviously. And to conceal the gap, add blue trim tape.

  5. Charles
    Posted November 1, 2013 at 19:36 | Permalink

    Hello and thanks for the reply, I am going with the electric version.
    I found an old plan published in the late 70’s.
    The specified dihedral was 3 inches under one tip.
    I have measured mine, and it is 3 inches! Nice accurate construction.
    If I put a 1/32″ balsa piece below the joiner piece, it gives about 3.3 inches, so about 10% more.
    Do you think this is about correct for the electric version?
    Charles

  6. Jon Gunnar Wold
    Posted November 1, 2013 at 20:58 | Permalink

    That sounds about right, although I don’t know the exact measurement, Hanno said only to increas dihedral slightly for electric. If you send me you e-mail adress I can share Hannos control throw details with you, he made a PDF with all his different settings for the ARF-model.

  7. Scott Sullivan
    Posted June 6, 2014 at 18:02 | Permalink

    Interested in the Curare ARF kit.

    What would the total price be shipped here in the USA to 63049 zip code?

    Thank you.

  8. Jon Gunnar Wold
    Posted June 6, 2014 at 21:11 | Permalink

    I don’t know, I don’t sell them. Ask Schweighofer, http://www.der-schweighofer.at

  9. alain
    Posted October 24, 2014 at 20:05 | Permalink

    Hi Jon,
    Very hard to contact you !!!

    I had a look on your F3A Plans; I initiate F3A flying in Switerland early 70ies with a superstar, followed by a Kosmo 3, a super Sicroly, a MK skymaster, two Mach one and, last but not least, 2 Mk Curare. I got some success on local competitions. But after I became a professionnal pilot and stopped model flying. Now, as retired, I’m rebuilding some vintage planes, most from scratch, or from eureka aircraft.

    I’m desesperately looking for a MK skymaster plan; it was one one worst pattern aircraft, but clearly the best in slow flying (very slow!)capabilities, and could do aerobatic like a backyard flyer.

    If you have na idea were I can find a plan, please let me know

    Regards

    Alain

  10. Jon Gunnar Wold
    Posted October 27, 2014 at 14:46 | Permalink

    I have an MK Skymaster 60 plan but I don’t know where it is at the moment (I’m rebuilding my house and everything is disorganized). If you give me your e-mail adresse I can send you some photos of the plan which I have on my computer.

  11. Didier²
    Posted September 26, 2016 at 14:27 | Permalink

    Hello.
    I’m a fan enthusiast of Hanno Prettner’s Curare. I have the same configuration as yours. OS 55 Ax and Sweighoffer Tuned Pipe. Can you tell me the distance from glow to tuned pipe cone to have best performance ? I never find this value anywhere. Thanks.
    Didier from France

  12. Jon Gunnar Wold
    Posted September 26, 2016 at 17:28 | Permalink

    Hi!

    My setup is 41,5 centimetres from the plug to the first baffle in the pipe, measured with a piece of string. Hatori pipe.

  13. Arthur Neto
    Posted January 12, 2017 at 00:38 | Permalink

    I had the privilege of meeting Hanno and Hans in Klagenfurt in 1981, and actually spent a couple of days in their Inn. We went to his field for a night-flight event, and the following day the event went on. Such humble, nice people! I miss Austria…

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