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Discussion in 'Firewall Forward / Props / Fuel system' started by ToddK, May 8, 2018.
D-Motor is what you are talking about but without supercharger.
Lots of used carbs from older 4 cylinder motorcycles are in the size range we need. There is also the option of scooter carbs like this one:
Modifying the existing carb may also be an option - see HACman modification.
Scooter carbs. A 150cc gy6 is ~9hp stock with a 24 or 26mm cv carb. There's a bit of headroom in the carbs. There are also 30mm tuning carbs for them, which should be about right for a 670. The 250 scooter carbs may be about right too. Then there are a zillion japanese multicylinder bikes.
Probably perfect for the twin cylinder engines since we have to use 2 carbs, but the single might work better with a 30mm carb?
I like D-motor. I wonder why they stopped short of supercharging, it would be a likely candidate for an altitude engine.
Motorav Brazil. VW based
Claimed 100hp@2900rpm direct drive
D Motor is nice!
I thought some of you would be up to speed with aero engines.
the D-Motor has had major problems, and they are redoing the design for the 3rd time.
Posted Oct 9th 2017
It is some time since our last news bulletin, so we thought it was time to update existing and potential customers about our future plans for D-Motor.
We will be continuing with production of the existing engine model and the launch of a proposed new version will be delayed by at least 2 years. This is to allow in-house development and testing to continue to ensure the engine will be fully reliable before any serial production starts.
As reported on 23 May 2017, one of the partners has left the company, which has obviously meant some re-organisation was necessary, but it has given us the opportunity to improve our systems and efficiency. The design has been frozen and the CAD and CNC libraries updated for all components.
We were manufacturing most components on CNC machines in our own factory although some parts were outsourced, such as camshaft manufacture, cylinder boring and Nikasil treatment / honing and valve seat installation. We have now decided to outsource the crankshaft and connecting rods to specialist companies in the UK. Line boring of the crankcase for crank and camshaft will also be outsourced.
Problems have been experienced during QC with a high rejection rate of the cast components caused by failures of the sand moulds. Working with our foundry company we have been running mould simulations to solve this problem and by the end of October we are confident that this issue will be eliminated.
In early 2017 we decided to stop serial production due to the casting problem, although sufficient parts were always held in stock to support any in-service engines. After customer feedback and comments at recent trade shows about the proposed new version we later decided to restart production of the existing model engine once the casting issue had been solved, but due to the re-organisation mentioned above this has taken much longer than we hoped.
Shortly we will be launching the first serial production batch of the 6 cylinderLF39 and a new serial production batch of the existing 4 cylinder LF26. As soon as these are available from stock we will re-start promotion and sales.
As you can see from this update they have been dealing with and over-coming a lot of obstacles encountered along the way as any small firm would! I agree that D-motor could be a lot more pro-active on the marketing of their engine line, however I think they are waiting until all ducks their were in a row and they could start a solid serial production of the engines. It appears as though Fisher Flying Products out of Canada will be the new Canadian distributor. Fisher has been in the business for many years and I doubt they would risk their reputation on a bogus design or poorly crafted engine. I do also wish their engines would be priced closer to the Jabiru 2200 and not the 3300 as it is. That being said I think this would be an amazing little engine for the SportCopter Vortex I am looking into purchasing. I also think it would make for an excellent choice on the Sonex Waiex I plan to build in the future, although I also like the UL260isA for this application. The D-motor engine may be a bit light for the heavier tail of the Waiex though... either way I see this motor finding market share in the years to come! I wish D-motor the success they deserve and feel every true aviator should feel the same way! Without new companies out there risking it all like D-motor we would all be selling our first born for a Rotax!
I think D-motor is an excellent concept. A concept that should be moved forward. With improvements, like a ADI crankshaft a blower and a propeller governor. Also either a two cylinder or a three cylinder version.
How does Motorav make max power @ 2900?
First you'll have to find a way to buy one. They come to shows, put up a booth, show an engine and make some videos. But they don't have a distributor here in North America, and no one knows how you'd get parts and service for one of these. Given that an airplane engine is likely to be in service for decades and that this one presumably has quite a few unique parts, placing a bet on an obscure Brazilian company that doesn't seem to be able to build a distribution network would be a risky proposition.
It has 2868cc, so has 32% more displacement than a 2180cc VW. The Revmaster R2300 (2331cc) VW claims 82 HP at 2950cc, which would scale up to 100 HP at this RPM if the Revmaster had the same displacement as the Motorav. Except, you can actually buy a Revmaster.
Custom head and case castings.
They are looking for a North American distributor.
Sounds like an opportunity for someone.
I want one!
Revmaster uses big valves, every one says to use small valves. So which is it?
Revmaster sells far more products to those building car engines than for airplane engines. This 049 head comes in a few valve sizes, and the 40mm x 35.3mm size is the smallest set they fit to that head. That's the size they put on their airplane engines. I don't think that means these are necessarily the optimum size for an airplane engine, just that they are the best of the stock sizes made by Revmaster. In automotive use, these heads are probably seeing 5000 RPM or more, so my guess is that the valves are oversized for our engines turning 3400 RPM max.
Until somebody builds a VW head expressly for airplane use, we'll be having to make do with car technology. On the bright side, because they sell tens of thousands of these parts to those building cars, sand buggies, etc, we get to buy them very inexpensively.
There was a kit once called "Dial a Jet" that you hand turned it, but IF you was ingenious enough to attach a Cable with a knob adjustment that you could adjust from the Cockpit might work. But EFI has so many Advantges over Carbs.
I think your all over thinking this. Most USA Part 103 Ultralights can't handle the Extra Weight of Engines much bigger than the Rotax 377/447 and Kawasaki 340/440 or Singles! You have Singles that make 54hp today. Most USA Part 103's don't need more than 25-35hp, and just about any Small 2 Stroke can make that without a Turbo. You only have 5 Gallons of GAS to play with, and you have a Max AirSpeed to contend with if you stay in the Rules.
Turbos are for Bigger Planes that need the 50+ HP and don't have the Weight Restrictions of Part 103!
100cc/7cc = 14.3hp
125cc/7cc = 17.9hp
150cc/7cc = 21.4hp
175cc/7cc = 25.0hp
200cc/7cc = 28.6hp
225cc/7cc = 32.1hp
250cc/7cc = 35.7hp
300cc/7cc = 42.9hp
325cc/7cc = 46.4hp
350cc/7cc = 50.0hp
375cc/7cc = 53.6hp Skidoo 377/380HO(368.4cc) 57.26hp@7000rpms, 52hp@6500rpms!
400cc/7cc = 57.1hp Simonini Victor 1 Super 54hp@6500rpms 400.5cc
Part 103 - 5 Gallons to Play with.
5.0/2.0gph = 2.5hrs of Flight or 2.0hrs with a Small Reserve.
5.0/2.5gph = 2.0hrs of Flight or 1.5hrs with a Small reserve.
5.0/3.0gph = 1.6hrs of Flight or 1.0hr with a Small reserve.
So what is going to be your Avg Fuel Flow per hour with these different Small CC Engines 100cc to 400cc?
I would say, the majority of Part 103 Ultralights need 18-20hp to maintain level Flight. A Rotax 277UL makes 20.3hp@5250rpms with a 1.9gph. With EFI you could maybe lower that.
As your HP/Rpms go up, your Flying Time goes down for Part 103.
140 kilos Static Thrust does that equal 264.6lbs of Force if I done my math right?
What HP and Cubic Inch/CC is that Engine?
Does your Plane with that Engine make USA Part 103 254lbs?
Motorav Brazil ENGINE SPECIFICATIONS:
Rated Power (HP)– 100 @ 2900 rpm
TBO – 1200 h
Number of Cylinders – 4
Bore (inches) – 3.878
Stroke (inches) – 3.701
Displacement (cubic inches) – 175
Compression Ratio – 8.5 : 1
Aviation grade, Octane 100 / 100 LL
Fuel consumption @ 75% (GPH) – 6.0 to 8.0
Dimensions & Weight:
Height (inches) – 20.5
Width (inches) – 30.0
Length (inches) – 27.4
Minimum runnable dry weight
including alternator(lbs) – 189
Type: Four-cylinder air-cooled horizontally opposed piston engine
Bore: 4.06 in (103.1 mm)
Stroke: 3.88 in (98.6 mm)
Displacement: 201 in³ (3.29 L)
Length: 28.53 in (724.7 mm)
Width: 31.56 in (801.6 mm)
Height: 23.18 in (588.8 mm)
Dry weight: 170.18 lb (77.19 kg) dry, without accessories
Valvetrain: Hydraulic lifters, two pushrod-actuated valves—one intake, one exhaust—per cylinder
Fuel system: Updraft carburetor with manual mixture control
Fuel type: 80/87 avgas minimum
Oil system: 6 US quart (5.7 L), wet sump
Cooling system: Air-cooled
Power output: 100 hp@2750rpm (75 kW)
Specific power: 0.5 hp/in³ (23 kW/L)
Compression ratio: 7.0:1
Power-to-weight ratio: 0.56 hp/lb (920 W/kg)
175ci vs 200ci.
2750rpm vs 2900.
7.0cr vs 8.5cr
1200hr TBO vs 2000hr TBO
$23,000 vs $??,???.
1000's of O-200's Flying vs ???? of the other Brand.
No, I'm not over thinking this. Many people other than me would love a direct drive, 30hp 70lb 4 stroke..
Doom awaits a $99 HF experimental engine or three first, though.
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