REFLECTOR: engine choice

Wed Mar 14 10:01:07 CDT 2007

If fuel consumption is king, then you will be hard pressed to find a 
solution better than an aircraft engine.
The bigger the cylinder, the slower the RPM, the better the BSFC ... 
generally speaking.  Note: generally.  Add electronic fuel injection, 
electronic ignition, variable valve timing, etc., and you get even better.

Since you are new, I'll repeat some concerns that I have.  Now I do not 
have any practical experience, only what I observe out in the wild.
I have a concern with very high power four cylinder four stroke engines. 
   This is one power pulse every 180 degrees of crank rotation.  That is 
one hell of a bang!  That 200-plus horsepower is concentrated into a 
very short crank angle.  This is hard on props, and all sorts of things.

If you wanted the best, I would say go with a diesel.  Actually, you 
have plenty of time to work this out, so a diesel may be an alternative 
by the time you are ready.  BSFC is good, it's cheaper, no spark plugs 
... all sorts of benefits, *plus* it's two stroke!  As smooth as an 
eight cylinder.

If you go with a six cylinder four stroke at least your power pulses 
begin to overlap.

If I were you, I would determine my flying profile.  Long business 
trips?  Puddle jumping?  Short strips?  Long runways?  High altitude 
airports?

Then determine what performance you need to meet your flying profile. 
You may find all you need is a little help every now and then with a 
couple of minutes of past redline power.  Perhaps it's a turbo.  Perhaps 
it's nitrous.  I like small efficient designs.  A smaller swept volume 
engine will generally get better BSFC than a larger engine at the same 
horsepower.  Your IO360 at 100% WOT will get better mileage than a 
throttled back IO540 at 60% power.  Notice I did not say at wide open 
throttle.

I like those little VW bugs with turbo.  Get the nice little engine 
sized for the majority of the driving it's going to do.  Now, add a 
turbo to give it that zip it needs to get in and around traffic.  Size 
your engine for good performance during cruise, or whatever type of 
flying you are going to do.  Sizing an engine for racing is completely 
different than sizing an engine for max economy.

Benedikt Harren wrote:
> Dear all,
>  
> thx for the helpful input. I am just trying to gather as much info as I 
> can. As for the rotarys fuel consumption seems to be quite high and with 
> aviation fuel prices of $9,82 / Gal. or 6,38 / Gal for auto fuel I want 
> to keep my fuel consumption to a minimum.
>  
> As for the rest of the factors that have to be considered when flying 
> n-reg experimentals in Germany:
>  
> - fuel costs --> low fuel consumption desired
> - very hard to get insurance; no hull insurance available through 
> european inssurance companies (certified engine might help)
> - short runways (2200'; which should be o.k. according to velocity website)
> - good climb performance needed because of lots of bad weather
> - high altitude capability to fly above weather (15000'-20000')
>  
> A turbocharged TSIO 360 might be able to meet the above criteria?? 
> Target cruise speed should be 200kts with CS prop. + with Klaus 
> Saviers's plasma ignition performance should increase and fuel flow 
> decrease especially when flying higher (12000') and using hard leaning 
> methods? Hope to see 200kts with 11,5 Gal, T/O within 1800 @ gross 
> standard day sea level. 
>  
> Has anybody any numbers or opinions on that? Anybody flying a TSIO360 SE-RG?
>  
> thx for the input,
>  
> Ben Harren
> ( Std RG Elite N888GF / just getting started)
>  
> ------------------------------------------------------------------------
> *Von:* reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] 
> *Im Auftrag von *Al Gietzen
> *Gesendet:* Mittwoch, 14. März 2007 01:41
> *An:* 'Velocity Aircraft Owners and Builders list'
> *Betreff:* Re: REFLECTOR: engine choice
> 
> Ben;
> 
>  
> 
> IMO; from the standpoint of both size and weight, I would not recommend 
> a V8 installation for a SE RG.  If you want to go ‘alternative engine’, 
> and want the HP of an IO540; but in a package that is smaller than an 
> IO360, and weighs significantly less than a 540 – then consider a 
> 3-rotor rotary, Mazda 20B.  You can see my installation, and the dyno 
> results of the engine on my website 
> http://members.cox.net/alg3/airplane.htm.  I am very pleased with the 
> performance and operation of this engine.  I only have 23 hours in the 
> air, so the reliability of my installation is still an unknown, but I’d 
> say there is little question of the robustness of the basic engine.
> 
>  
> 
> The spar on the long wing (at the inboard end is something like  2” 
> wider than the short wing.
> 
>  
> 
> Speaking of low-cut keel, I wonder to what extent it reduces the 
> structural strength of the bottom of the plane.  As one who experienced 
> a gear-up landing a couple of months ago (yes; I’m trying to forget, but 
> there it is), the strength of the keel down the middle really kept the 
> damage to a minimum.  Had that failed and allowed the bottom to ‘cave 
> in’ at all, it would have been a much larger repair job.  The other 
> thing the saved it was the microglass hardpoints for the cylinders and 
> the seats which served a skid pads.
> 
> But, then; you should never have to plan for a gear-up, or gear collapse 
> – right?
> 
>  
> 
> Al (repaired and painted, waiting for a prop)
> 
>  
> 
>  
> 
>  
> 
> *Subject:* REFLECTOR: engine choice
> 
>  
> 
> Hi all,
> 
>  
> 
> I emailed with scott b. today regarding tools for my shop (just getting 
> started) and the dual yoke option (with low cut keel). I also asked him 
> about engine choices and told him that I was thinking about going 
> automotive (once I get to that point). I have looked at Bill Mulrooney's 
> V-8 installation which looks very promising (good T/O & climb 
> performance + low fuel consumption + lots of HP). I have a Standard RG 
> Elite model and was wondering if the smaller wing will be able to take 
> the load of the heavier engine installation (similar to an IO-540)? 
> After all, the only difference between the long and the short wing seems 
> to be the wing itself, since the main spar looks identical !? I also 
> noticed that load factors, published on the velocity website for the 
> XLs are smaller than the ones for the Stds, letting me belief that the 
> wings are of similar strength? I was just wondering what the group's 
> input was on this (V8 installation with gross weight increase to 2800).
> 
>  
> 
> Anybody else flying or building a V8 velocity?
> 
>  
> 
> Kind regards,
> 
>  
> 
> Ben Harren
> 
> ( Std RG Elite N888GF / just getting started)
> 
> 
> ------------------------------------------------------------------------
> 
> _______________________________________________
> To change your email address, visit http://www.tvbf.org/mailman/listinfo/reflector
> 
> Visit the gallery!  www.tvbf.org/gallery
> user:pw = tvbf:jamaicangoose
> Check new archives: www.tvbf.org/pipermail
> Check old archives: http://www.tvbf.org/archives/velocity/maillist.html