Wispa (oz11115)

 

Wispa - plan thumbnail image

About this Plan

Wispa. Radio contol sporrt model for electric power with Speed 400 motor.

Quote: "In the search for a handy, small, electric model, John Digby designed this model for use from small sites for two or three function radio.

Want a small model for those smaller flying sites? Want a model that you can lose in the back of the car? Want to try electric without committing yourself to lots of expensive cells and motors? Well Wispa could be the model for you!

My original Wispa was built back in 87 and designed around the readily available and very cheap Mabuchi 380S motor since I wanted a model that would allow me some evening flying on a nearby small field. I have flown electric 'only' since 1985 so the form of propulsion was obvious, but what type of model should I build? A small glider was considered but I envisaged landing problems as, although the site was fairly open, it was surrounded by a low hedge. I finally decided upon a high wing cabin type model mainly for ease of flying and construction. The model was built as per rudder/elevator version detailed on the plan with the exception of the wing which was a tissue covered open structure, the plan shows a different version suitable for film covering. I have built two further wings as per plan and these have proved adequately strong.

Performance with 5 x 550mAh cells and a 5-1/2 x 4 prop was very good - not bad since the total cost of motor/cells/prop was less than £10. Wishing to keep things as simple and cheap as possible, I had not fitted any form of motor control. Knowing that there would be insufficient power to make use of a speed controller I had considered using a relay switch operated by the throttle channel but dismissed this as I wanted the option of fitting a 2 channel radio that had been sitting idle in the workshop for sometime.

One solution would have been to operate a microswitch on full deflection of the elevator servo. I had heard of this used on electric sailplanes but eventually considered it inappropriate for this type of model. The solution came via a letter from long time electric flyer George Bushell. At the time I was editing Electric Flight UK newsletter (now official newsletter of the British Electric Flight Association) and George had written in with details of a similarly powered electric sailplane. Of particular interest was the description of the motor switch used. This consisted of a simple small toggle switch protruding from the underside of the fuselage extended by a short length of plastic tube - an empty 'biro' refill in this case. Operation is simply a matter of push forward and launch. When insufficient power is available to maintain flight the model is landed and the tube knocks the switch to the off position. Suffice to say the tube must be long enough to prevent the prop hitting first and stalling the motor. George reported that he had used this method on previous models with no problems.

The fitting of a fuse is recommended - a 10A automobile type is sufficient - as soft landings in long grass do not always activate the switch. I found out the hard way!

During the past few years several other suitably sized motors have become available. A good replacement for the 380S is the 380SH now becoming well known as 'Speed 400' from Graupner. This motor is wound for use with 6-7 cells and is recognisable by its metal backplate. When used with 6 x 600mAh cells this combination is hard to beat for the money.

A short list of recommendations is listed on the plan. This includes the Kyosho AP29 which, in its cheapest form, is 3 times the price of a Speed 400 but which does give an increase in performance. The most powerful motor I have used is the Astro 020 as it is one of only a couple available for use with less that 6 cells..."

Wispa, R/C Model World, June 1993.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.

Corrections?

Did we get something wrong with these details about this plan (especially the datafile)? That happens sometimes. You can help us fix it.
Add a correction

Wispa - completed model photo

Datafile:
  • (oz11115)
    Wispa
    from RC Model World
    June 1993 
    36in span
    Tags: Electric R/C Cabin
    all formers complete :)
    got article :)
  • Submitted: 18/04/2019
    Filesize: 421KB
    Format: • PDFbitmap
    Credit*: Circlip, RFJ

003.jpg
003.jpg

Do you have a photo you'd like to submit for this page? Then email admin@outerzone.co.uk

User comments

No comments yet for this plan. Got something to say about this one?
Add a comment

 

 
 

Download File(s):
 

Notes

* Credit field

The Credit field in the Outerzone database is designed to recognise and credit the hard work done in scanning and digitally cleaning these vintage and old timer model aircraft plans to get them into a usable format. Currently, it is also used to credit people simply for uploading the plan to a forum on the internet. Which is not quite the same thing. This will change soon. Probably.

Scaling

This model plan (like all plans on Outerzone) is supposedly scaled correctly and supposedly will print out nicely at the right size. But that doesn't always happen. If you are about to start building a model plane using this free plan, you are strongly advised to check the scaling very, very carefully before cutting any balsa wood.

 

Terms of Use

© Outerzone, 2011-2019.

All content is free to download for personal use.

For non-personal use and/or publication: plans, photos, excerpts, links etc may be used, provided that full and clear credit is given to Outerzone with appropriate and specific direction to the original content i.e. a direct hyperlink back to the Outerzone source page.

Unauthorized use and/or duplication of this material without express and written permission from this site's owner is strictly prohibited. If we discover that content is being stolen, we will consider filing a formal DMCA notice.