# The big engine small plane problem

### Help Support Homebuilt Aircraft & Kit Plane Forum:

#### akwrencher

##### Well-Known Member
HBA Supporter
Obviously I'm pretty far out of my league here as far as experience goes, so I'll just whisper some thoughts.....

W 10 tailwind wing area is 92 sq ft, can keep up with older lancairs, and can be built very nice and still cheep. See Jan 2011 kitplanes for an example of a very nice one.

Not advocating this design in particular, but for cruise performance per build dollar it's hard to beat. Depends on how fast you need to go though....

Someone said earlier that Cert engines don't have modern FI with alt comp etc. Not true. On a hombuilt you can put whatever you want on that "cert" engine, and give it modern FI tech.

#### SVSUSteve

##### Well-Known Member
Someone said earlier that Cert engines don't have modern FI with alt comp etc. Not true. On a hombuilt you can put whatever you want on that "cert" engine, and give it modern FI tech.
I have a feeling that comment was said with a healthy dose of sarcasm.

#### Toobuilder

##### Well-Known Member
HBA Supporter
Log Member
Keeping an engine alive by stirring all the handles seems like a holdon from a bygone era to me...
While this is true compared with modern cars, we should also recognize that the typical "transport category" mission profile as discussed here is pretty easy to manage if you have the correct instrumentation. For example, a typical flight in the RV has me advancing the throttle to full on takeoff (and not touched again until near the destination), maintaining 100 ROP EGT (1250, in this case) untill level off, and managing RPM with the blue knob to meet my climb requirement (generally 2450ish). At level off, blue knob screws out until 2350 RPM, and I use the lean find function on the EMS to set the mixture to 50 LOP. This whole process from brake release to cruising LOP is 10-15 minutes tops. From then on I have 5 hours available to just watch the world slide by at 165 KTAS and 8.0 GPH. My only "management" function is switching tanks once per hour.

#### Jay Kempf

##### Curmudgeon in Training (CIT)
While this is true compared with modern cars, we should also recognize that the typical "transport category" mission profile as discussed here is pretty easy to manage if you have the correct instrumentation. For example, a typical flight in the RV has me advancing the throttle to full on takeoff (and not touched again until near the destination), maintaining 100 ROP EGT (1250, in this case) untill level off, and managing RPM with the blue knob to meet my climb requirement (generally 2450ish). At level off, blue knob screws out until 2350 RPM, and I use the lean find function on the EMS to set the mixture to 50 LOP. This whole process from brake release to cruising LOP is 10-15 minutes tops. From then on I have 5 hours available to just watch the world slide by at 165 KTAS and 8.0 GPH. My only "management" function is switching tanks once per hour.
Switching tanks once and hour seems sorta old school too. Two pumps and one Arduino controller. But that's just me Kidding.

#### Toobuilder

##### Well-Known Member
HBA Supporter
Log Member
I'm with you my friend... I'd like nothing more than an "ON/OFF" control!

#### SVSUSteve

##### Well-Known Member
I'm with you my friend... I'd like nothing more than an "ON/OFF" control!
There's a reason why I'm designing an non-gravity fuel system with a "BOTH" option on the fuel selector. There are several reasons I'm not going with a gravity-feed system but that's a major one.

#### akwrencher

##### Well-Known Member
HBA Supporter
Not at all. Just seemed like there was some debate between old airplane engines and modern car engines. The beauty of Experimental is that you can mix it up. Get the best of both technologys. That is, if your checkbook can handle the heat
I have a feeling that comment was said with a healthy dose of sarcasm.

#### bmcj

##### Well-Known Member
HBA Supporter
Aren't there any mechanically adjustable (in flight) "big" props? Such a two-speed prop is far simpler as an CS prop and works just as well.
Are you familiar with the Aeromatic? Ground adjustable semi-constant speed prop.

#### Autodidact

##### Well-Known Member
[h=2]Re: The big engine small plane problem [/h]
I'll take it over the big plane small engine problem!

##### Well-Known Member
Are you familiar with the Aeromatic? Ground adjustable semi-constant speed prop.
Familiar, no. Never seen one up-close. What I've read and heard is rather contradictionary, one side sees them as expensive, unreliable, while most owners seem perfectly happy with them.
Unfortunately, last time I checked they were MORE expensive as an electric prop from MT. (Just under 10K US$...) I'll take it over the big plane small engine problem! I wouldn't. Flying an 1800 lbs sailplane with 30 HP is a lot of fun #### akwrencher ##### Well-Known Member HBA Supporter #### Toobuilder ##### Well-Known Member HBA Supporter Log Member I know there are fans of the Aeromatic, but I have a buddy who put one on his 125 HP Swift without success. Despite spending several days with the company owner fiddling with it, the prop never performed all that well. Maybe others have had better luck, but the Aeromatic is off my candidate list. BTW, if anyone wants the Swift or prop, it's available for the taking at the bottom of Cheasepeak Bay. #### SVSUSteve ##### Well-Known Member I wouldn't. Flying an 1800 lbs sailplane with 30 HP is a lot of fun Yeah, it's probably a bit fun but not terribly practical for anyone who isn't a glider junkie. BTW, if anyone wants the Swift or prop, it's available for the taking at the bottom of Cheasepeake Bay. As in a Globe Swift? #### Toobuilder ##### Well-Known Member HBA Supporter Log Member Yes. He had unexplained engine stoppage and ditched about a year and a half ago. He and his mother survived the actual ditching, but she succumbed during the failed rescue attempt. #### SVSUSteve ##### Well-Known Member He and his mother survived the actual ditching, but she succumbed during the failed rescue attempt. Yeah, I think I heard about that. He had unexplained engine stoppage and ditched about a year and a half ago The NTSB put it down to a mishandled fuel selector valve and fuel starvation. They said they recovered it from the bay. Either way, condolences to your friend and his family. #### Dan Thomas ##### Well-Known Member Someone said earlier that Cert engines don't have modern FI with alt comp etc. Not true. On a hombuilt you can put whatever you want on that "cert" engine, and give it modern FI tech. It's also not true in the real certified world. See http://www.lycoming.com/news-and-events/pdfs/iE2_Engine.pdf This engine has been available for some time now, but the very slow GA production market, the declining pilot population, the recession, and the cost of airplanes (mostly due to the stupidest litigation laws in the world and the greed of people), all conspire to make it unlikely that any of us will fly one anytime soon. When I started flying in 1973, I flew an "old" 172: it was a 1966 model. Seven years old. When I left the flight school a year ago, we were using airplanes as old as 1973: 39 years old, and that is typical of a lot of places now. (We did have a 2006 172, but those cost$300K now). With declining interest in aviation and a smaller pilot population, there's no market for new engines or airplanes. If that Lycoming IE2 had come out in 1976, the peak of GA production, they'd be all over the place.

But they're not. The fact that they're only now showing up is due entirely to the cost of certification; again, due to the propensity of people to sue the pants off anyone having absolutely anything to do with an airplane in which they get hurt (and they usually get hurt because of their own mistakes, not any manufacturer or mechanic), and the FAA succumbs to public demands that airplanes be 100% safe. Achieving even 99% is really expensive and time-consuming.

So let's not blame the engine makers for being decades behind in fuelling and ignition technology or anything else. The fact is that most of us would never have learned to fly at all if it wasn't for their continued production of "antiquated" airplanes.

Dan

#### Detego

##### Well-Known Member
The fact is that most of us would never have learned to fly at all if it wasn't for their continued production of "antiquated" airplanes.

Dan

I see cost and performance of these "antiquated airplanes" as the reason why more people don't fly; this lead me to investigate Homebuilt Designs like the KR2, Jeffair Barracuda and BD-4, using Auto Engine conversions in the mid 1970's.

Fact is, most peoples itch for flight can be served nicely with a powered paraglider.

#### SVSUSteve

##### Well-Known Member
Fact is, most peoples itch for flight can be served nicely with a powered paraglider
And you're basing your opinion on what precisely?

#### Toobuilder

##### Well-Known Member
HBA Supporter
Log Member
Back to the topic at hand- I'm looking at the typical overpowered two place design for my own needs. I have been going along the big inch NA powerplant (540 Lyc or V8) route so far. I wonder though, if you took something like a 300 HP Rocket and replaced the engine with a normalized 180, how it would perform?

As I sit in my fuselage mockup and ponder the V8 integration, I can't help but consider the 180 Lyc sitting in the corner. If I add a turbo, would I come out ahead...

#### akwrencher

##### Well-Known Member
HBA Supporter
Interesting. If you only neaded the hp at alt, and climb, etc. was still acceptable, that might be a good option. Just out of curiosity, what are you building?
Back to the topic at hand- I'm looking at the typical overpowered two place design for my own needs. I have been going along the big inch NA powerplant (540 Lyc or V8) route so far. I wonder though, if you took something like a 300 HP Rocket and replaced the engine with a normalized 180, how it would perform?

As I sit in my fuselage mockup and ponder the V8 integration, I can't help but consider the 180 Lyc sitting in the corner. If I add a turbo, would I come out ahead...