I'll bet you've never seenone of these before! Brian Sichi's "Guidato."

[David Davis]

Despite having many other calls on my time including two more models in build and three needing repair, I decided yesterday to start building Brian Sichi's "Guidato." I wanted a vintage model with a tricycle undercarriage and I rejected other possibilities like the Rudder Bug or Waveguide simply because I'd seen those models in flight and I've never even seen a Guidato! Besides I like its snub-nose appearance! The plan is available on The Outerzone: https://outerzone.co.uk/plan_details.asp?ID=7378 I intend to use it as an ab initio trainer with retired beginners before they move on to a four channel ARTF trainer.

 

I will make a few structural alterations like adding an elevator and enlarging the rudder. I was tempted to simplify the wing construction by using two spars at the widest point of the wing rib and a supplementary spar half way to the rear a la Super 60 and so many others but I think I'll keep the wing structure pretty much as it is though I may use slightly different size spars to suit what I have in stock. The plan calls for 1/8" (3mm) balsa wing ribs. I have sufficient 1/8" sheet in stock but I may use foamboard for the wing ribs if the cognoscenti think that it would be suitable. I've never used foamboard before.

 

I intend to power it with an 30 fourstroke.

 

Note my usual immaculately tidy workbench.

 

 

[GrumpyGnome]

That's certainly a little ...... different!

[Graham Davies 3]

Hi DD,

 

Since discovering foamboard, I use it for ribs on most of my models. Unless they carry significant landing loads, it works fine, is easy to cut, makes little mess and is dirt cheap. Light too.

 

Beware that whilst it has a very slight grain, it has nothing like the grain strength of balsa so can be very fragile if it is narrow. For example in smaller ribs where the spars are close together. Oh, and it does tend to blunt your blades quite quickly.

 

Otherwise it's a great alternative material

 

Graham

[Eric Robson]

I would have probably made the whole air frame in foam board with a little ply at mounting points for wing , engine and  undercarriage. I don't do ribs just spars, my wings are flat bottom and work fine. construction is quick, cheap, and easy.

I also do traditional building but started doing alternative building when the balsa shortage came to us.

As Graham said the worst part is blunt blades they come without warning and half way through a cut start tearing, still not the end of the world.

[David Davis]

I am still working on the Guidato's fuselage but I have been looking at the structure of the wing. By modern standards it's pretty unconventional! The leading edge is 1/4" sq obechi. The forward lower spar from 1/8" sq obechi. The upper spar is from 1/4" sq obechi and the main spar from 3/16" x 3/4" hard balsa. The dihedral braces are from 1/4" plywood. Picture below. I do not have any obechi but I have balsa, basswood and some spruce. I also have a few questions!

Question 1. What is the point of having such a small 1/8" sq spar as the lower front spar?
Question2. What is the point of having staggered spars instead of having one spar above the other at the wing rib's widest point?

Part of me wants to replicate the original construction and I have some 1/8" sq spruce which I could use. On the other hand I could move the front lower spar backwards to a position directly beneath the upper spar thereby producing a D box which I think would produce a stronger wing. That said, I am not an engineer. I was thinking of using basswood for the upper spar and balsa for the lower one and joining the two together with inter spar webs. I have several sheets of hard 3/16" sheet balsa from which I could make up the main spar.

The entire model seems to be over-engineered. There are gussets all over the place in the fuselage tying in the longerons, uprights and cross members. Most of the wing ribs are made from 1/8" balsa they are spaced at 2" between centres and surely 1/4" ply dihedral braces is overkill!

In 1957 the Guidato would have been loaded with a much heavier radio than we currently use so perhaps that's the reason for all of this strengthening of the structure and the use of obechi.

I'd be interested in your views.

[David Davis]

Progress on the construction of the Guidato has stalled for several reasons but I hope to get on with it next week.

Part of the last week has involved teaching my protegé Frans how to both build and fly. He has reached the stage where he can take-off, fly circuits and horizontal eights and land his Junior 60 without any involvement from me. One more flight on the buddy box and he's on his own as far as I'm concerned, on his Junior 60 at least!

I also finished the repair of Uncle Geoff's Double Size Tomboy. I ran out of Vintage Yellow Solartex and as it's not made anymore, I was forced to finish the forward fuselage in Red Solartex. I've flown it twice in the last two days. The OS 40 Surpass turning a 13x4 prop is more than adequate. I managed a fifteen minute flight with it yesterday and still had a little fuel left in the 4ozs tank.

I've built the Guidato's fuselage sides and cut out the F1 and F3 formers. These are the first main formers in the fuselage structure, F1 being the firewall and F3 the former beneath the wing's leading edge. F2 gives shape to that part of the fuselage between the firewall and the windscreen. The F3 former is supposed to be made from 1/8" (3mm) plywood but I didn't have any. I decided to use the hardwood engine bearers as per the original because I felt that they would strengthen the nose and I made an F3 former out of basswood sheet. It was not a success so I made up two new formers from 1/4" ply of which I have considerable stocks. Having roughed out the shapes I screwed the two of them together using servo screws. By carefully cutting the holes for the bearers and the slots for the longerons in both formers simultaneously, I should have something which will fit. The engine bearers are cut from 5/8" square oak. I did not trust my planing skills to reduce them to 1/2" square section as shown on the plan so they've gone in full size. They should be ok for reducing vibration and adding a little weight to the nose! Since taking the picture I've I've cut out a 2.5" (6.4cm) hole in F3 with a tank cutter in order to save weight. The steerable noseleg mechanism I have re-cycled from some long-dead foamy trainer.

[David Davis]

Fuselage taking shape.

[David Davis]

Fuselage now framed up in SLEC jig. Note Miss Blue Eyes' Secret purple and pink Skyrider in the background!

[David Davis]

The fuselage is now complete apart from the nose blocks. It requires a little making good in places, some filler and a great deal of sanding! The fin and rudder are simply posed on the fuselage for the picture and are not permanently attached. The entire fin looks small to me compared with a Junior 60 or Super 60 which are slightly smaller models. I will measure them up and see just how much smaller the Guidato's fin really is. I have sheeted the fuselage bay forward of the leading edge of the fin in sheet off-cuts in case I decide to fit a strake. One thing to bear in mind is that the Guidato's fin is thicker than the other two models so that may have a bearing on matters.

I am going to have a go at replicating the original undercarriage except that I shall use springs where the designer used rubber bands. I have a pair of undercarriage legs from some long dead ARTF trainer which will serve as the main gear after cutting them to fit. Soldering was never my strong suit so if i make a horlicks of things I will use a proprietory undercarriage.

[David Davis]

Soldering has never been my strong suit but to my surprise and delight I've made up a servicable undercarriage! OK the track is wider than the original, there's some more cosmetic work to be done on the soldered joints and there's considerable reinforcing to be done inside the fuselage, neither have I fitted the forward dowel but it looks like it could work. There's nothing bolted up in the picture but it's starting to take shape.

[Mike Etheridge 1]

I remember the Guidato, it was shown on the front of an Aeromodeller magazine between 1961 and 1963. I do have the magazine and will scan the cover but I am currently having problems on the website.

 

[Mike Etheridge 1]

A better picture  is attached. The cover picture is described as follows: 'Gaynor Holden a charming assistant for Alan Whittaker and his AM25 powered ''Guidato'' made from A.P.S RC/677 (9 shillings including post)!) and fitted with a Hill receiver plus Mactuator. Seen at the 1960 Woodford Rally sponsored by the Stockport Advertiser'.

[Outrunner]

Nice on Mike. Anyone know what a "Mactuator" is?

[PatMc]

A Scottish enforcer.

[EarlyBird]

A magnet actuator, apparently.

 

Mactuator, November 1954 Air Trails - Airplanes and Rockets

 

Steve

[Mike Etheridge 1]

A Mactuator (I still have one somewhere) was used to operate the rudder movement on single channel model planes. It was wired to the receiver and consisted of an electro magnet which closed with each press of the transmitter button. It also had a 4 pronged wheel that would turn a quarter of a revolution with each button press, so the rudder would move full right and then neutral and then full left and then neutral. It was rubber powered so you needed a device to wind up the rubber, I used an Elmic Side winder. I  employed this arrangement on my 1962/3 built Junior 60 which still exists. The Mactuator was fixed to a ply bulkhead about 8 inches from the rudder and a piano wire shaft was fixed to the Mactuator and extended through the back of the fuselage and cranked to link on to the rudder. The Sidewinder was mounted near the front of the plane. A drawing would make more sense I think ?.I was hopeless flying the JNR 60 with the Mactuator and eventually installed a Sanwa 'Mini Two' proportional radio some 10 years later. The JNR 60 now has 2.4GHZ radio.

[PatMc]

Frank, you are describing a rubber band powered escapement,  the link in Steve's post seems to show that the Mactuator is a battery powered magnetic actuator.

[Mike Etheridge 1]

Here is the Rip Max 'Mactuator' (Model Aircraft Actuator) advertisement from the june 1962 Aeromodeller:

 

[Mike Etheridge 1]

Patmac

 

I used a Macgregor 'Terrytone' receiver in the JNR60 and it only needed an Eveready 1289 battery to power both the receiver and the Mactuator. The 1289 battery delivered 6 volts to the receiver and the receiver fed the Mactuator.

 

[PatMc]

Frank, I take it you didn't check out the link in Steve's post ? It would seem that the name "Mactuator" was also used by Howard McEntee for his magnetic actuator. 

I couldn't recall an escapement going by the name "Mactuator"  hence why I was puzzled by your reference to rubber power & the Elmic Sidewinder.

BTW I do remember the the Sidewinder & rubber powered escapements, in fact I sold several Elmic esc's on Ebay but I still have a R-E compound esc+ motor esc together with a matching pulse generating joystick.

 

 

 

  

[Nigel R]

On 04/07/2022 at 07:53, David Davis said:

was tempted to simplify the wing construction by using two spars at the widest point of the wing rib and a supplementary spar half way to the rear a la Super 60 and so many others but I think I'll keep the wing structure pretty much as it is though I may use slightly different size spars to suit what I have in stock.

 

Fuselage is looking good DD.

 

If you've not already started the wing, I would flat out suggest redesigning the structure. The shown structure looks goofy and doesn't tie up the elements that provide strength very well. Make the wing into a standard well proven D Box structure. Foamboard ribs - 2" spacing, 3" spacing, whatever you want. Cutting foamboard ribs takes very very little time, once you've made a ply template.

 

I would also make the tailplane flat. Because, if you're going to use foamboard, the tail can be chopped out from foamboard in about two minutes and edged with 3/16" sq balsa in another ten. If you want a fancier appearance you could put some 1/16 square strips running fore/aft on the upper and lower surface to make it look like you did a built up, but I'm fairly certain I'd not bother myself!

 

[PatMc]

@Mike Etheridge 1 , seems I had a few senior moments yesterday, I'll try not to refer to you as "Frank" in future. ☺️

Edited August 5, 2022 by PatMc

[Mike Etheridge 1]

Anyone that remembers Mactuators and Sidewinders must be having senior moments by now Patmac.

 

[David Davis]

6 hours ago, Nigel R said:

 

Fuselage is looking good DD.

 

If you've not already started the wing, I would flat out suggest redesigning the structure. The shown structure looks goofy and doesn't tie up the elements that provide strength very well. Make the wing into a standard well proven D Box structure. Foamboard ribs - 2" spacing, 3" spacing, whatever you want. Cutting foamboard ribs takes very very little time, once you've made a ply template.

 

I would also make the tailplane flat. Because, if you're going to use foamboard, the tail can be chopped out from foamboard in about two minutes and edged with 3/16" sq balsa in another ten. If you want a fancier appearance you could put some 1/16 square strips running fore/aft on the upper and lower surface to make it look like you did a built up, but I'm fairly certain I'd not bother myself!

 

 

I know what you mean Nigel but if you make too many changes, is the model still a Guidato?

 

I have good stocks of balsa and no immediate plans to build another model which would use it so I'll carry on.

 

[David Davis]

Starting to take shape. Nothing has been glued to the fuselage. The tail plane and fin are simply wedged in place. The tailplane was built with one spruce and one hard balsa spar because that was all that I had in 3/16". It requires the tip blocks to be glued into place.

 

Wings next!