Our Plane Project - YIPPY-I-O
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Page 6 - 2008
Page 7 - 2009

What is a Yippy-I-O?
Well it is our own designed plane based upon other kitplanes. Our fuselage is fiberglass and comes from the Australian made Terrier (highly modified as you will read further down). We are using the aluminium RV6 wings and empennage.

What's the name Yippy-I-O about?
In Australia for many years we have been able to reserve callsigns while building. The best unused one we could find on the register was VH-YIP, so we had it reserved for a year and it was coming up on renewal when the department suddenly got excited and said you can't reserve call signs anymore. So Doug rang their office in Canberra and started weeping in the phone about his sorrows of losing YIP, etc. The guy couldn't swim and his office was filling with water so he gave us the option of registering the airplane immediately even though not yet built, but it had to be done tomorrow and the nearest place to get the form Caccy 123 was Townsville (350K - 170miles away). The next day we leapt in our Super Mouse and went to see CASA in Townsville.

They came out with a fistful of forms and said we had to fill in ALL the boxes. The lady then looked at Doug's face and said "I'll help".
She asked who is the aircraft manufacturer? Doug looked sideways and said "It is an Experimental or Homebuilt aircraft".
She replied, "who is the manufacturer", so we called it a 'DougLish'.

On we went, length, span, -
"What is the serial number"? 001 (We weren't quick enough, we should have said 007)

How many engines, wheel placement, -
"What is the model of the aircraft"? Doug said tongue in cheek "a Yippy-I-O",
(I had trouble with my face & bolted out the door at this) Doug expected her to say "be serious what will we put here".
Instead she said "how do you spell that?" So Doug spelled it out. We now have the official registration papers for a Douglish Yippy-I-O VH-YIP

So, as we are flying into controlled airspace, we will be calling up Tower, "
Yankee, India, Papa, a DougLish Yippy-I-O inbound from the ....". Other traffic will be told "You are number 2 to the Yippy-I-O on final".
Can you hear the reactions from towers and other pilots?
Our bureacrats get all serious, so we thought we would chuck a spanner in the works by putting some fun back into aviation. And best of all we got it past them. Of course we may end up in chains if they read this - but -................

Concept of the Yippy-I-O

As you read on Doug's page, he has been the developmental pilot for the Aerolite 1+1 kit plane (Now renamed the Terrier) built in Mackay, Queensland. It is a fiberglass fuselage with a Stits high wing.

Terrier 100.

We liked the shape and sleekness of the fiberglass fuselage. However, we are not keen on high wing aeroplanes (personal preference) + we wanted to cruise at around 130-150 kts (harder to achieve on less HP, than a low wing). So we began searching for the ultimate wing, aerobatic a must. After much research, we finally decided upon the RV6 wing.


1. The RV6 has a gross weight of around 1600lbs, the Aerolite about 1200lbs gross. We estimate finishing at around 1400lbs with all the comforts of a car. Air-con, heater, center stick for uncluttered cockpit.

2. The RV6 wing is stressed to +/-6gs at gross weight and we intend to perform aerobatics in our plane. This wing regularly exceeds 200kts on the Harmon Rocket, which we don't intend to cruise at, but gives us an excellent margin between our cruise and Vne speeds. With so many RVs around it is a very well proven wing. With a lighter engine, we expect our gross weight to end up lower (1450 lb) so we should have an even greater margin of safety.

3. Even though we are going for a fiberglass fuselage, we like the thought of having aluminum wings. That way we won't have the wing dissolve away if fuel leaks + particularly in our climate, where the temperature regularly exceeds 40 degree C during summer on the tarmac, we don't want to go out one day and find the wings looking droopy, or clapping hands..

On the right is an early computer generated image of how the plane could end up looking. The image was created using the blue plane above and the photo of another kit plane the "Sprint" below.

Many changes have been made since this photo was created. We are now going to use the RV6 wings as stated above instead of the Sprint, plus we are also using the RV6 tail section, as we need the extra control for the strong crosswinds we have on our airstrip and the elevators were in the wrong position on the Terrier to recover from a spin.

On the progress page you will see the tail being grafted onto the fuse, (we actually had to add 9" to the Terrier fuse). Once this was accomplished, we were able to take the whole she-bang outside to photograph it, then this pic was used to scale an outline into a CAD program in company with an RV6 outline.

Now we could start comparing apples to apples, and getting our dimensions sorted out. Our weight and balance said that substituting the Lycoming with a Subie (120 lbs less) would require changes, as you can see below

The lighter motor (120 lbs) changes the Cof G, and you will notice the seat will be made to lay back for wet fly-in accomodation.

Design Philosophy

The engine hasn't been too much of a problem. We always knew we were going to use an EA81 and we have now bought one. In EAA's Sport Aviation, Van once commented that "every one wants to add power, no one thinks of LESS" Well our turbo EA81 will develop 117 HP at 4600 rpm, which we may run thru' a VW final drive (1.4 to 1) to get 3300 rpm for our 66" prop. We will need a longer t'off run than an RV6, but by 8,500 feet, we can cut back to 4,100rpm and still produce 110 hp, where a 160 Lyc at 65% will generate 104 hp, so even with the deeper fuse (I like to sit higher), at 150 lb lighter we should be in the ball park for speed. In reality we will probably cruise around 4,000 rpm (100 hp), I would like to cruise at 130+knots with a fuel burn of 4-5 gph.


We have considered both the direct drive option as well as the possibility of a reduction. At this stage we are inclined towards the reduction configuration for the engine. We looked at an Australian made helical gear redrive the Oz drive, and seriously considered building our own from a VeeDub final drive hub, but will probably settle on a Hirth.
We also intend to use an in-flight adjustable propellor, probably from Mr Ivoprop.

Page 6 - 2008
Page 7 - 2009