Sunday, July 6, 2014

FDI out and about

Saturday, July 5, 2014

Nico Kohne enjoying FDI

the final product of this blog doing what it it was intended to do!!!....

Wednesday, March 2, 2011

Luggage bin and cubby hole box

I finally installed the luggage bin. Philip Darne discovered a neat little box at Midas which works well as an armrest and place to store your cellphone, keys etc.

Saturday, December 12, 2009

Bethlehem airshow

Bruce Perkins always seems to get good pictures of Whispers. Here is a shot of the "blog plane" during the Bethlehem airshow. Murphy's law resulted in the radio aerial wire getting a dry joint upon arrival at Bethlehem...hence the use of the handheld radio

Monday, July 20, 2009

Tailwheel - sealed bearings

The imported tailwheel is supplied with unsealed bearings. These are ok if greased regularly. If you are not keen on removing your tailwheel often and/or operate off a muddy dirt strip you may want to consider installing sealed bearings. Unfortunately the unsealed bearing is 1+3/8" (imperial). A local metric bearing can be made to fit but the bore in the wheel needs to be opened up slightly to 35mm. Two adapter spacers also need to be made for the centre of the bearing (see pic).

Sunday, June 21, 2009

Glide tests

Testing the actual glide performance of your motorglider is fairly simple. I chose a "dead" winter's day with little or no thermic activity and did a series of climbs to just over 3000'. I then cooled the engine for a while, shutdown, feathered the prop and closed the cowlflaps. I established a pre-determined glide speed and maintained this as accurately as possible. As I descended through 3000' I started the stop watch and noted the time every 100'.

Monday, May 25, 2009


Saturday 23rd of May was the day. All went well. The cooling was one of the unknowns BUT even during a sustained full power climb I cannot get the oil temp above 95C. Water stays at around 80C. Engine off glide performance seems good. MGL EFIS is behaving well. Hobbs time already 2.1 hrs after 7 short flights over the weekend.

18/6/09 - testing still going well. Apart from a stuck needle and seat in the one carb there have been no snags.

Tuesday, May 19, 2009

spoilers - bungees

Here are pics of how I attached the bungees, pulleys and saddles.

Monday, May 11, 2009


The signage shop decided to supply the reg as ZJ-FDI. I assume it is because of the presidential inauguration that was happening that day. So apart from waiting for a "U" letter and the official paperwork -she is ready!!! After the final inspection and whilst doing the engine ground runs I did taxi on the runway a few times. Observers are convinced that they saw a few mm of sky between the tyres and the ground but that of course is not possible. Hopefully will have the paperwork by the coming weekend.

Mass and Balance

I love this task....because it means you're nearly ready to aviate!

With zero fuel and full oil we positioned ZU-FDI on the 3 scales with the canopy sills level. Using a plumbbob and a long tape measure we determined the distance between the wing leading edge and the main wheel centreline and the tailwheel centreline. Determining the exact position of the humans and fuel is normally a little difficult so this time I climbed into the aircraft whilst it was on the scales (not that easy!) and from the readings worked back to obtain the exact moment arm. I did the same with the fuel. See spreadsheet below.

Rear wing attach bolt

Please don't forget this all important bolt! Apart from flight loads it also looks after the fore/aft loads imposed by exuberant wing handlers on the ground. One needs to decide whether to make it perpendicular to the top wing surface or the bottom. I prefer to split the difference which will result in moderately tapered stepped spacers - BUT they will be required top and bottom.

Drill the hole 7.5mm and REAM 5/16".

Wednesday, May 6, 2009

Final cockpit layout

The beauty of building your own aircraft is that you can tailor the cockpit to exactly what you want. Personally I like to have it as simple as possible hence the spartan layout that you see in the picture. If the fuel is turned off the lever pokes into your leg thereby reminding you. The fuel sight gauge is against the tank hence it can be accurately calibrated for the 3 point attitude on the ground. Prior to take off the total will be entered into the EFIS which will then determine fuel remaining by means of the fuel flow. The electrical system is also very simple with automotive blade type fuses which can be removed if a system needs to be disabled.

Trailering to the airfield

This 90km trip happened last wednesday just in time for the Whisper Fly in.

In the interim I painted the wings and fitted them to the fuselage. This weekend I will attach the ailerons, setup the aileron travels and weigh the aircraft.

Next week it is paperwork and then we fly - watch this space!!!

Aileron pushrods - reaming the bushes

The teflon bushes are built into the wing. They start out with a 19mm hole into which the pushrod fits snugly. If left like this there is too much friction in the system. To eliminate most of the friction one can ream the bushes "in situ". Various reaming devices work but the most successful so far seems to be a step drill. (Thanks Kelvin!)

Spoiler torque tube ends - final fit

Tighten the AN5 bolt, roughen the inside of the torque tube and the outside of the bush and glue in place with pratley 5 minute quicksteel or equivalent. Once cured drill through with a 3mm drill and insert an M3 s/s machine screw with nyloc nut.

Aileron bellcranks

A good staring point for determining the length of the aileron pushrods is to adjust all the rod ends to about mid travel and with the wings on, set the aileron bellcrank with its long axis aligned perpendicular to the wing spar.

The hardware used with the these bellcranks is shown in the pic.

Aileron pushrods - joint near wing split line

It is possible to use an aluminium extrusion to fabricate this bracket but it is a difficult size to source. An easier option is to fabricate one from 1.6mm stainless steel.

Top cowl flaps

I am normally not in favour of complicated mechanisms and hence normally use a simple cable mechanism to close the top cowl flaps. If one wants to adjust the amount of opening of the top cowl flaps in flight though - quite a bit of force is required to overcome the aerodynamic loads on the flaps hence I am trying an electro mechanical setup. I hope to be able to close them partially in flight. Whether or not the system works remains to be seen - watch this space! Oh and if the electrics fail I have a cord that I can pull in the cockpit which disengages one of the ball ends connected to the cowl flaps thereby opening one of them in an emergency.

Tailwheel - locking pin

In a previous post I described the manually unlockable tailwheel with the pin that one tends to lose! How about making up a pin like the one shown below. Its easier to use and to prevent losing it you insert it into a storage hole drilled near the end of the control horn.

Canopy hinge door - final fitment

All painted and fitted with the proper hardware!

Friday, April 17, 2009

Bleeding the brakes

The pics show the routing of the brake pipe. If you are having brakes for left and right seat pilots then you require 2 master cylinders with reservoirs and two without reservoirs. The ones with reservoirs are the most "upstream". The Grove parts come with a sketch showing how to plumb all of this. I am installing the cylinders with the reservoirs on the pilots side (left). These then route to the co pilot cylinders and from there to the wheels. Bleeding is easiest with an oil can connected to the bleeding nipple via a short length of flexible tube. Pump fluid in until the pilot's reservoirs are full. You need a helper to tell you when to stop!

Thursday, April 16, 2009

MGL EFIS - installed

Is'nt that a pretty sight!

It is a really nice piece of equipment and easy to configure and install