Dimona H36 Sauer 2500

June 2007

It climbs like a homesick angel, goes like a scalded cat and is as smooth as a babies bottom. ZDD, our Dimona H36 with its new Sauer 2500

It flew finally Tuesday 5th June 2007. Solo was a good 600ft/min + and dual was a little less but prop needs resetting a bit to get closer to the 3000rpm on take off so expect 700ft per min but need to check on the logger to get true readings.

There is still a day of little things to do - prop need repositioning (compression is so good it will only stop in one position) and bit more cowl problems, and adjustable prop pitch a few times

Ashley is prepared to come out if somebody would help him clean wings as there is a problem where both wings have been sprayed with metal from angle grinder

Things to remember with Sauer are

1 Turn on only the magneto to start (if you have electronic on then starter button will be DEAD)
2 Set throttle full back to start (Bing Carby) and remember choke only enriches fuel in Bing
3 Cut back power quickly after take off (read Sauer book)
4. THIS ENGINE WILL SUFFER FROM CARBY ICING so whenever near cloud base and low engine revs USE CARBY HEAT ALWAYS Why do you ask .....well this engine has cool outside air going in and this more power and climb rate instead of the old system of protected warm air always going in to engine.
5 And engine has hydraulic valve lifters so it is no longer necessary to do tappets every month..... YEA
6 Read notes about electronic ignition - it says "If magneto fails fly to nearest airport but if electronic ignition fails then keep flying to your own home airfield"
7 Avgas is recommended but Autofuel 98 can be used in emergency

Since I returned from Melbourne I have worked 3 weeks straight ZDD (in between flying) I would really like to thank Ashley has been out 5 days a week and worked non stop in between baby feeding. Also Allan Rundle worked like a non-PC for 3 days over last weekend, Giles came out on each day off and Ray came to sort out my disasters and is still needed to sort out brakes. I think I could right a book now for the correct order to do man of the jobs. Also Rowan dropped all and did a 1 hr welding job on Monday. Also Todd Clark for visiting Sauer near Mainz in Germany to look into Sauer and sending little aviation parts needed form time to time.

People ask why a Sauer! Well it has hydraulic valve lifters (even fuel injected L2400 in Michael Shirley's Grob still has mechanical valve lifters!!! ), engine has TBO 1600 hrs, sodium filled valves, huge heads with black colour to get rid of heat, and lightweight permanent magnet Kabota alternator and I gather a heavy duty front bearing.

What happens now? Well all things now are minor and placards need sorting out and a flight report goes to John Viney and then it is again a certified aircraft!!!!! probably next week. It will need regular oil changes and I suggest 2HRS, then 12HRS TT then 25HR TT (2hr, 10hr, 15hr) and oil is real cheap Use Castrol magnetic 10W-40 and NOT Castrol GTX 2 20W-50

McPhee

It is very usual these days for all aircraft to have dual ignition and dual fuel pumps (except Cessna high wing and tanks overhead) one pump is mechanical on engine and the other is electric usually near fuel tank to pressurise fuel line rather than suck (which can give vapor lock and engine failure) This is the reason electric fuel pump is on on take off to say 500ft

Firstly let me explain ignition system

The Sauer has one Magneto -Magneto is magnets and a coil which generate spark WITHOUT a battery and the click is the impulse magneto which gives a spark even if turned slowly. When you turn it off (down) it earths out spark and this is like the motor mower. (The Jabiru has dual magneto but it should not start on the ground - no impels click - so you must spin at a high speed and have a good battery) This is the lower RED SWITCH as it always has been.

The Sauer also has a backup electronic ignition and like the car is run by the battery and this system churns out a real good spark BUT it must not be OFF when the starter button is pressed. It is top RED switch In fact if you turn it ON the button will be totally DEAD. Starting with both ignitions on could do serious damage to engine so it is designed you can not do the wrong thing.

So the correct ground start up procedure would be
(1) Turn Master on (Red Bone) and have radio off
(2) Turn Electric Fuel Pump ON and listen for click of pump as fuel goes thru
(3) Set throttle
(4) Turn magneto ON - bottom red switch up
(5) Insure backup ignition is OFF
(6) Press starter and adjust throttle so engine runs smoothly (not coughing and spitting please) and run at 1000 to 1500 rpm for first 2 minutes - taken from Sauer book
(7) CHECK oil Pressure by pointing to oil pressure gauge and if no pressure then TURN OFF IMMEDIATELY
(8) Turn on secondary ignition (top red switch UP)
(9) Consider turning fuel pump OFF for ground taxi and this way you are checking Mechanical (engine) fuel pump
(10) Turn radio ON and pause at "SQ" to listen that you have correct volume then go thru to normal
(11) Turn on and set Electric vario. and now is a good time to check it is charging (ILEC vario gives accurate readings at "BAT" position
(12) Now is the time to start Taxi and give a call "entering and backtracking" and LOOK before going onto active runway (this is one of the major problems at busy airports if you read CASA publications. Consider using Carby heat while on the move if humidity is high but do not do this on dry outback airports as when carby heat is on it is unheated air.
(13) at end of runway do our checks F F F F and C C C C and now we must add M M and T T
                F    Fuel tap ON
                F    Fuel sufficient for flight
                F    Fuel pump on
                F    Frequency set
                C    Choke off
                C    Carby heat off and checked
                C    Cowl flap open (only Falke YHB)
                C    Canopy locked and LOOK at catch please
                MM Check both ignition systems by turning one off at a time then BOTH ON (with Sauer digital RPM only works on magneto)
                T    Trim set for blue line take off speed
                T    Check Time piece.
and consider a take off radio call airport is busy.
and smoothly advance throttle over a count to 5 - DO NOT apply or change power suddenly as you have a huge flywheel up front and it goes thru a crankcase which you can consider is an egg shell. This applies to all aviation engines and especially the big Lycoming as they have counter weights which could get flat spots and just destroys engine at $40K damage

At the moment as it gets run in oil temp rises and pressure falls so keep speed up and revs up. DO NOT labour engine in cruise with high nose at slow speeds and high throttle settings. Just like a car going up a hill change gear or lower nose.

What I like to do with a new glider (in this case Dimona is a fair bit different with New carby heat, new dual ignition and new engine revs and temps and would apply to Grob 103c III SL) I have a person sit in the glider close their eyes and go thru various procedures. All this is up to Cliff the clubs CFI but I am sure he will not mind as already I am seeing people can be confused by the new procedures in Dimona and I am sure they will not mind me naming them as it was Giles Taylor and John Witham.

Talked to John Viney today and he is preparing the new C of A with Sauer S2500 which is only a formality. I would like to get more data on the runway length required (short grass for motorgliders) to clear a 50ft obstacle as engine runs in. Already after 2hrs the engine is freeing up. Other data needed time ground to 1000ft which seems like 350ft in one minute and 950ft in 2 minutes at 700kg AUW and about 22deg nil wind.

Just to explain Sauer it has hydraulic valve lifters (no other such engines have this feature) sodium filled valves (no more burnt valves and heads off and these are usual in real Aviation engines), dual ignition system for reliability, much bigger heads - thicker and much more fin area and painted black, a huge front bearing not a toy car one to support the propeller, carby heat which means cooed of $50+ aviation prices) air can go into carby which means more power especially on take off, oil filter and oil cooling with air going in and out its own system and does not interfere with engine cooling and a permanent magnet generator with no brushes or slip rings for reliability, auto spark plugs ($7 instead of Aviation plugs at $50+) and finally a light geared starter motor (does not come in spinning into flywheel like happened in early Limbachs in older Falke. All this is reliability in an engine. ,

In case you have not read flight manual amendments for sauer below are some of the important stats

Max revs 3000rpm for Max 5 minutes (93.6HP)
Permanent Max 2700rpm (80HP)
No load speed 700rpm (but would suggest a little more and Digital Tacho may not record correctly could be double!!!)
Fuel AVGAS 100LL or 100/130 (almost the same in AUS) or if unavailable 98 octane auto fuel but in hot weather Sauer say "steam bubbles may build up and in those circumstances we strongly request you use only AVGAS 100".
Oil 3.5 lit (min 2.5lit) 10W-40 quality oil and we use Castrol Magnetic
Oil pressure max 4.5 BAR, 2.0 BAR at 2000rpm, 1.0 BAR idle
Oil temp most favourable 80degC to 100degC (Min 50degC to Max 120degC)
Cylinder head no 4 max 230deg C - which I personally think is far too high
Carby Ice can be expected with high humidity and low engine revs either on ground or at cloud base. DO NOT sit idling engine unless you add carby heat and I do expect more carby ice problems with this engine so be on guard for same.
The TBO of this engine is currently 1600hrs. (Magneto service at 500hrs)
And for record bore is 97mm stroke 84mm displacement 2481cc, compression ratiop 9.0:1 , plug clearance 0.7mm (and no tappet data! - like any decent car engines has had for the past 30 years -yea)

It has a rate of climb of about twice the previous engine so on Passenger and training flights engine will get used 1/2 as much!!! Caution as it could be using 20 lit or more per hour for full power flying. Cruise fuel consumption should be closer to 13 lit. per hr but I am only guessing so take extra fuel. The 2 useless things in aviation is fuel back in shed and runway behind you.

ZDD has grown a bit in weight- On a long touring trip with luggage and fuel on board you may be at or near the Max AUW of 770kg. All I say is in take off break the ground and maintain chair height as the speed builds up and then climb away at say 5kts more than usual. During the flight you will use up fuel and in all cases you will still be within the C of G. with low fuel when you land. If you have to land for some unknown reason maintain an extra 5 to 10 kys right to the ground and all will be well. If you ever fly with an aft C of G it could not be nice in handling but it will perform well in the glide and and if you fly with a forward C of G the round out may be difficult. Personally I like to fly any glider I fly with C of G 2/3 to 3/4 back -ie an aft C of G. This is very important with Grob SL GLL which I discovered this week, but that is another story and another email.

To shut off engine book quotes "After running with high power let engine run approx 3 minutes by 1000rpm" I would suggest we continue with our present proceedure and I will be adding a KSA Shock cooling alert, overtemp alert and digital CHT. degC This will be set so that if you bring power back too quick a yellow light will flash and buzzer will sound. Damage is done to aviation air cooled engines by rapidly cooling from a high temperature to a mid temperature and not from a mid temp to a low temp. These instruments are used in most glider tow planes in Australia and are considered engine insurance policy. Craig Bird's green Cessna has had a cracked cylinder at cost $1800 and Canberra Gliding Club had 5 out of 6 cylinders in their Pawnee cracked with a bill close to $10K! and the public servants in the club there did not get a Shock Cooling Alert!!! at a cost of about $400. Crazy

In wintertime Sauer suggest "cover part of oil cooler otherwise your temperatures will not reach 80 deg C

In Tropical areas "shorten time between oil changes and if dusty clean air filter every day!!!" and it was underlined in book. Martin at Sauer warned me the airfilter is on the small size and the K&N high air flow must always be used and not a paper air fliter.

FOR DIs
Always check the prop change arm bearing are clear of back of prop as it is now very very close and may cause future problems - we already had to visit aero welder Monday to get more clearance.
Check all cable ends (throttle, choke, carby heat) as all is new and could be a problem
Check cross wires for security
Scan entire engine with your eyes and undo things with your fingers
Check operation of prop change mechanism
Check HT ignition leads and especially as the wires come out of the 2 green ignition coils high on firewall.
Extra caution pulling thru the prop as engine has very high compression
At some time I would ask you to think what all the 5mm tubes are for everywhere. They all have a purpose.
Oil changes for a start are to be done at 2hrs TT (now due), 12hrs TT and 25hrsTT then back to Sauer 25 hly changes
Spinner screws
Exhaust for cracks - it is of new manufacture and there could be a problem

And when flying ALWAYS BALANCE OIL TEMP AND OIL PRESSURE by adjusting airspeed, nose attitude and engine revs - think ahead of the problem if you can.

Sorry about the long rant but it may avoid explaining to pilots individually - and please ask if you are uncertain on anything.

Sauer_flight_manual_performance.doc