www.davidcookaviator.com
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DAVID COOK AVIATOR |
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Greg Pedersen
Streak Shadow ZU-BFO
E-mail converstaions with other Shadow pilots about modification.
1st Batch of E-mails
From: Ajab Khan
Sent: 08 July 2002 11:44 PM
To: Greg Pedersen
Subject: Re: Streak Shadow Microlight
Dear Mr Pedersen,
What a pleasant suprise to get your mail. BTW my thanks to your friend for her assistance. Yesterday
after we spoke I sent you am SMS message on your mob phone. Perhaps it did'nt get to you. Infact I had heard a lot from David about your streak and also seen a photo when I visited him at Leiston last year. I had the pleasure of David visiting us in Pakistan to help in our repairs.
Let me tell you something about our star streak. We got it in bits and pieces from Airborne Innovations in the US, whom we finally sued for having deceived us in sending an incomplete kit and instruments. Nevertheless with the help of David, CFM and many nice guys in UK I finally got the long range fuel tanks, engine mount, and now the carbon fibre landing gear, Cowl etc. It has a 912S (100hp) rotax driving a arplast wide chord 52" prop (now after the force landing a wood GSC wide chord 52"). In addition to cope with our intended long distance flying we had the following additionals installed :-
1. pannier carbon fibre tanks 17 lits each
2. Fibre glass Aux tank under the engine 26 lits
3. Main fibreglass slipper tank enlarged to 46 lits
4. ELT artex 200
5. Transponder Garmin 320 with mode C
6. Icom A23 with a 10 watts linear amplifier
7. Hamilton Vertical card compass
8. Electric attitude Gyro
9. Rocky Mountain micro encoder( ASI.VSI, ALT, OAT, Pressure / Density ALT, alarms for various
speeds and alt etc) one small display
10. Rocky mountain Micro Monitor ( EGT.CHT, FUEL FLOW/PRESS , OIL TEMP/PRESS, CARB
TEMP, TACH,RPM,FLTtimer,GMT clock, manifold PRESS with alarms)
11. ANR headsets with walk man stereo system
12. Tempur Foam cushions
13. Dimple tape on the upper wing surfaceWe have flown it for approx 150hrs before the force landing. Max alt with two up and 80lits of fuel was
14500 feet AMSL, and with a density altitude of approx 17000feet. We tried to fly over the base camp of Mount K2, but clouds blocked our route. My partner flew with a ferry tank in the rear cabin for 9.20 hours non stop, covering a distance of 750 miles (head wind 10-15 knots for 4 hours). In our effort to get max performance from the aircraft we have tried various things like the half cowl, dimple tape, wheel pants, and now a different prop. The speeds we get at gross wt of 450 kg are as fol:-
1. Max at 5700 rpm is 105 kts TAS
2. At 4600 rpm is 72 kts
3. 5000 rpm 82 ktsI would like to know of all the modification you have done to your streak shadow and what performance figures do you get. I would certainly be pleased to see pics of your lovely aircraft. I am sending a few pictures of our Star Streak. Looking forward to hearing from you.
With kindest regards to you
ajab.................................................................................................................................
Original Message
From: Greg Petersen
Sent: Monday, July 08, 2002 10:53 PM
Subject: Streak Shadow Microlight
Dear Mr Khan,
Following our conversation on Saturday morning that was cut short, I eventually contacted David Cook in England who gave me as much information as possible to contact you. We have tried to piece together email address possibilities, so you will hopefully get one of these.
David did give me a fax number as well and I will send you a fax just in case you do not receive this message.
Once we have established a successful way of communicating, we can get onto the subject of all the modifications that I have done to my Streak Shadow which you and David have no doubt discussed.
Like David, I don't own a computer so my friend, Lindsay, has offered the sevices of her email and fax facility. She also has a scanner and I so can send you photos of my aircraft.
Regards,
Greg Pedersen
Durban, South Africa...................................................................................................................................
Dear Ajab,
Here is some of the information you wanted in respect of my Streak. We started building the Streak in January 1997 which took approximately eight months. I then took the basic aircraft home in August and started the moulds which were built over the engine (see photos). I hand-carved the moulds all by line of sight using no specifications. I had no idea at the time if this would actually work but had a basic idea in my head and the end goal was to streamline the back as much as possible.
Right from the start of this project I did consult with David on all my ideas and basically had his approval that it would work. At the same time I made the moulds for the wheel spats, the underbelly and the flaring under the wing which reduces drag considerably so I had been told.
The interior cockpit I covered in black denim material to reduce reflection on the inside canopy. I made my own custom built/shaped foam cushions. To date the aircraft has done 270 hours of flying.
Here is a list of the cockpit instruments and some specs :
Volt Meter
Fuel Gauge
RPM Gauge
Oil Pressure Gauge
Oil Temperature Gauge
Digital Clock with outside and inside temperature reading
These are all standard VDO automotive gauges.
Vertical Speed indicator
Airspeed indicator
Alt. meter
Cylinder Head Temperature Gauge
Aircraft Compass
Carburettor Heat and Choke
Landing lights
Navigation light
Instrument lightsMicro-air 760 radio with 4 watt output connected to a flightcom-intercom system. This has been fitted to an additional consol between the legs and is joined to the floor and main panel.
Icom A3E handheld radio 1,5 watt as a backup - this was my original radio Garman GPS 3 with moving map A piece of 'high-tech yellow knitting wool' as a slip indicator taped on the front canopy. I have left a space for a micro-air transponder which is at present rather expensive - approx. R17 000.
Speeds that I have attained so far :
Flat out - 110 mph or 95 knots at 4500 ft.
115 mph or 100 knots at sea-level and at a 50 - 100 ft per minute descent I easily touch 130 mph.
My comfortable cruise speed is 80 mph or 70 knots.It was necessary to do 40 hours' proving flight for our civil aviation authorities within a 50-mile radius only, which took me some time, as I only fly on weekends with friends.
Ajab, if you look at the original pictures of the moulds and new photos I have taken (which are still to come), you will see that I have had to make extra ventilation at the rear and have now finally found the happy medium in respect to cylinder temperatures which, during flight, sit at between 240 and 250 F and oil temperatures at about 85 to 100 degrees C on a hot day with a tail wind, but mostly sits at about 85 to 90 degrees C.
I use Avgas 100 LL and oil used is Aeroshell W100.
Like you, I have been through numerous propellers from the original Arplast 52" narrow cord (you have a photo) to various wood experimental and wooden ground adjustable to finally a 48" four-blade fixed-pitch propeller which has given a fair, allround performance and superb smoothness although creating a bit more drag. This propeller was custom-built for my Jabiru engine. Maximum r.p.m. is 2900; 2500 - 2600 r.p.m. at 80 mph cruise speed.
I have a recently proven fuel consumption of 8,5 litres per hour along the coastline at normal cruise speed with no passenger. With a pass per hour at approximately 4 000 - 5000 ft altitude.
With passenger, I use about 11-12 litres I have one of the early Jabiru 2200 cc 80 hp engines which was found to produce in reality only about 75 hp (British figures). So, unlike the higher power difference between your Rotax engine and mine, my climb-out rate is probably not as 'supersonic' as yours but more sedate at approx. 500 - 800 fpm. Any engine with a gearbox has a huge advantage over a direct-drive engine, in my opinion.
Our airfield is 2600 feet above sea level so all our flying is done at between that level and 10000 feet. I have only been up to 11000ft once, by myself, along our Drakensberg mountain range which has an average height of 10000ft and have never really felt the need to go higher but I must give it a go sometime. On that particular day, the temperature was about 6 degrees and I never did work out what the density altitude was.
What long trips have I done recently? A friend of mine, Jas, who also has a Streak, and myself flew from Cato Ridge to Plettenburg Bay in the southern Cape recently, a distance of approximately 630 nautical miles. It took us 6 hours 55 minutes. We made three stops en route to stretch legs and refuel. Jas has a Rotax 582 engine which uses between 15 and 19 litres per hour so it was necessary for us to stop, especially at East London International airport, because no-one else has Avgas.
I carry 35 litres in my slipper tank plus a 75 litre ferry tank on the back seat which gives a total of 110 litres and with a fiiel burn of say 10 litres per hour at cruise speed, I could happily fly for ten hours non-stop which would be equivalent to about 800 miles at an average of 80 m.p.h.
I have just taken more pictures of my wing and rear view of the body and propeller for you to see, so as soon as I have them, I will ask Lindsay to email them to you. I hope you will find it interesting.
I fitted six stall fences to the upper surface, vortex generators to the top leading edge of the wings and enclosed the gaps on the upper surface of the alerons to reduce turbulence and drag. I will relate my findings to you in this regard when we send the photos.
For interest, we have three Streak Shadows and one Star Streak (the only one in the country) in our club and I will get the guys together sometime for a photo and a separate picture of the Star Streak. This aircraft has a similar engine to mine but with no canopies or cowlings (the original raw manufactured state but very well finished). But guess what, he cannot keep up with me! It would seem that all the streamlining that I have done, really has made a difference!
Lastly, before I go, is there any way of getting videotapes of footage that might interest you (my plane, our club, fun days, etc) to you safely. If so, I could make copies and send them to you. We use VHS tapes in South Africa.
Take care,
Greg
E-mails from Greg Pedersen S.A.