# spec list of efficient light planes

### Help Support HomeBuiltAirplanes.com:

#### Toobuilder

##### Well-Known Member
HBA Supporter
Log Member
Interesting that one of the most obvious measures of a transportation device's "efficiency" is NMPG, yet that metric is absent in this thread so far.

Happy to throw my 2 passenger, 300 HP Rocket's typical 20 NMPG "efficiency" metric into the mix.

#### patrickrio

##### Well-Known Member
Weedhopper
Easy Riser
CGS hawk ultra
Mitchel wing
VJ 24?
Aerolight 103
Looks like the Weedhopper, Easy Riser, CGS Hawk, VJ-24, and Aerolight 103 cannot fly 63mph with 26hp so I have not included them. If you have specs that show one or more of them can do this, please send me links to the relevant specification sheets.

3 models of mitchell wings that are capable of flying 63mph on 26hp have been added to the list.

#### patrickrio

##### Well-Known Member
Interesting that one of the most obvious measures of a transportation device's "efficiency" is NMPG, yet that metric is absent in this thread so far.

Happy to throw my 2 passenger, 300 HP Rocket's typical 20 NMPG "efficiency" metric into the mix.
If you gift me that plane, I would be happy to change the list requirements so it can be included!

NMPG, or MPG or GPH etc would be great metrics to have on the aircraft included in my list.... but the info is often just not available on spec sheets. Once I have a stable spreadsheet, I will try to contact manufacturers etc to get missing information.

##### Well-Known Member
Log Member
The Skylite will do it but you need to build it yourself from plans.

#### patrickrio

##### Well-Known Member
The Skylite will do it but you need to build it yourself from plans.
The specs I found show it as 60mph with 28hp... Just below the cut off for inclusion. I think maybe it might make it with a full canopy and teardrop shaped aero on wing support tubes and gear legs?

#### BJC

##### Well-Known Member
HBA Supporter
The specs I found show it as 60mph with 28hp... Just below the cut off for inclusion.
But you have kept the Whing Ding, which also doesn’t make your cut off speed, and just barely flies with a really light pilot.

BJC

#### henryk

##### Well-Known Member
They can show
=auer "GREEN" KASPERWING can fly with horisontal speed 18 km/h ( 5 m/s !),
and climbe with 40 deg. angle...

#### Attachments

• 65 KB Views: 12
• 69.4 KB Views: 12

#### patrickrio

##### Well-Known Member
But you have kept the Whing Ding, which also doesn’t make your cut off speed, and just barely flies with a really light pilot.

BJC
Whing Ding has been taken off, as well as all others that can't go 63mph on 26hp. See current list below:

Last edited:

#### patrickrio

##### Well-Known Member
=auer "GREEN" KASPERWING can fly with horisontal speed 18 km/h ( 5 m/s !),
and climbe with 40 deg. angle...
I love the Kasperwing... I used to be able to ride my bike to the factory/airport where they were made in Issaquah, WA when I was a kid. But unless it flies 63mph or faster on 26hp or less, its off this particular list. If there is a specifically modded version that meets these criteria, i will include it if there are pics of the mods.

#### jedi

##### Well-Known Member
Interesting that one of the most obvious measures of a transportation device's "efficiency" is NMPG, yet that metric is absent in this thread so far.

Happy to throw my 2 passenger, 300 HP Rocket's typical 20 NMPG "efficiency" metric into the mix.
We engineers need to get some sort of conversion factor for KW/NM.

#### patrickrio

##### Well-Known Member
We engineers need to get some sort of conversion factor for KW/NM.
would most prefer KW to HP? NM to Miles(SM)? I actually already converted many of these to "Mercun Freedum" units since most of us are US located. If we are talking full on engineering list preference, maybe converting it all to metric is best?

I felt that since this list is mostly manufacturers/builders/designers self reported numbers the data would contain some of the usual truth stretching anyway and would not be particularly useful for true engineering but rather for rough comparison and preliminary investigation purposes.

As far as "distance per gallon" specs, I will work to include them where available or possible to calculate.

#### Hot Wings

##### Grumpy Cynic
HBA Supporter
Log Member
Interesting that one of the most obvious measures of a transportation device's "efficiency" is NMPG, yet that metric is absent in this thread so far.
Factor in your Person NMPG and it likely gets even better.

I'd like to see an added column for flight hours/energy costs........solo at (Vx+Vy)/2. We have very different missions.

#### speedracer

##### Well-Known Member
I love the Kasperwing... I used to be able to ride my bike to the factory/airport where they were made in Issaquah, WA when I was a kid. But unless it flies 63mph or faster on 26hp or less, its off this particular list. If there is a specifically modded version that meets these criteria, i will include it if there are pics of the mods.
Steve Grossruck used to fly his Kasperwing at Dog Mountain, WA in late 70's, early 80's as a foot launched hang glider. It had about the same performance as the hang gliders of that era. One weekend he let a guy fly it that had no experience at all in that glider. The guy had no problem at all. Did a good landing too.

#### Toobuilder

##### Well-Known Member
HBA Supporter
Log Member
If you gift me that plane, I would be happy to change the list requirements so it can be included!

NMPG, or MPG or GPH etc would be great metrics to have on the aircraft included in my list.... but the info is often just not available on spec sheets. Once I have a stable spreadsheet, I will try to contact manufacturers etc to get missing information.
My response was somewhat tongue in cheek (considering this is the "light stuff" subforum), but was meant to illustrate the lack of well defined requirements in the OP. It appears you are looking for help in conducting a trade study, but you have not clearly defined what "efficiency" means to YOU, the customer. To ME, light aircraft efficiency is defined by the least expensive cost to move payload over distance. Since "time" is a "cost" to me, then speed is a compelling factor. For someone else, "efficiency" might be the payload/empty weight fraction, or speed range (stall speed/cruise)...

Ive been involved in trade studies on combat aircraft development before, and its amazing where the requirements will drive you if one stays pure to satisfying the performance needs above all else. You might have an idea of what the vehicle looks like at the beginning but it might end up completely different at the end. I was on one project that started out as a metal wing/body/tail and ended up as a composite tailless flying wing.

Airplane selection is either emotional or requirements driven. Pick one and stick to it.

#### patrickrio

##### Well-Known Member
Steve Grossruck used to fly his Kasperwing at Dog Mountain, WA in late 70's, early 80's as a foot launched hang glider. It had about the same performance as the hang gliders of that era. One weekend he let a guy fly it that had no experience at all in that glider. The guy had no problem at all. Did a good landing too.
Dog Mountain is the ****. Love that place.

#### patrickrio

##### Well-Known Member
My response was somewhat tongue in cheek (considering this is the "light stuff" subforum), but was meant to illustrate the lack of well defined requirements in the OP. It appears you are looking for help in conducting a trade study, but you have not clearly defined what "efficiency" means to YOU, the customer. To ME, light aircraft efficiency is defined by the least expensive cost to move payload over distance. Since "time" is a "cost" to me, then speed is a compelling factor. For someone else, "efficiency" might be the payload/empty weight fraction, or speed range (stall speed/cruise)...

Ive been involved in trade studies on combat aircraft development before, and its amazing where the requirements will drive you if one stays pure to satisfying the performance needs above all else. You might have an idea of what the vehicle looks like at the beginning but it might end up completely different at the end. I was on one project that started out as a metal wing/body/tail and ended up as a composite tailless flying wing.

Airplane selection is either emotional or requirements driven. Pick one and stick to it.
There are definitely better, more accurate measures of efficiency than I am using. I, like you, am also particularly interested in "cost per mile." The issue is that most available data on light aircraft does not include these better measures, and if data does exist, it doesn't exist in consistent form from aircraft to aircraft. I would love CAFE quality data on all of them, but it just doesn't exist. I don't think ANY of them have CAFE data. So I selected two pieces of data that DO exist universally (mostly) max level speed and engine power. If max level speed or HP does not exist, I look at the other data to see if it SEEMS like the aircraft will meet the criteria.

What this list DOES show is airplanes that can get from point A to B with low energy expenditure. Where planes are expensive, their design features can be observed and maybe someone can use the inspiration to improve a less expensive option.

As far as it being a "Trade Study" I assure you, I am not currently in any related trade. I have always wanted to work in the aviation industry, but my opportunities keep being elsewhere....

PS. that composite flying wing sounds interesting.....

#### Toobuilder

##### Well-Known Member
HBA Supporter
Log Member
"Trade study" is simply a tool used to make decisions. If you pick up two different jars of salsa at the market, compare ingredients and price and then pick the most favorable, you have performed a trade study. Comparing aircraft specifications against requirements to determine the most favorable is also a "trade study"... It looked to me that your spreadsheet was the basis of your own trade study (because thats exactly what is done), so that explains my confusion.

See! you were on your way to a legitimate performance analysis and didnt even know it. You fit right in with the rest of us.

Last edited:

#### Vigilant1

I'm enjoying the spreadsheet, but just to mention it: For a "typical" regular Joe/Jane considering airplane ownership for recreational use, the fixed costs (hangarage, insurance, annual inspection, opportunity cost of $$"invested" in an airplane, etc) can easily add up to more /flight hour than the cost of fuel. These other costs are very situation specific, so not especially amenable to inclusion in a spreadsheet. But anyone doing the calcs for their own "affordability ranking" should definitely look beyond fuel burn per mile (or fuel burn per hour). If a hangar costs 200/mo and the plane is flown 50 hours/year, that's 48 per flight hour. Reducing fixed costs ( sharing a hangar, trailering the plane home, being able to do inspections under a Repairman's Certificate, avoiding or reducing insurance costs, etc) can make a much bigger difference in the bottom line than trying for minimal fuel burn. Last edited: #### patrickrio ##### Well-Known Member I'm enjoying the spreadsheet, but just to mention it: For a "typical" regular Joe/Jane considering airplane ownership for recreational use, the fixed costs (hangarage, insurance, annual inspection, opportunity cost of$$ "invested" in an airplane, etc) can easily add up to more $/flight hour than the cost of fuel. These other costs are very situation specific, so not especially amenable to inclusion in a spreadsheet. But anyone doing the calcs for their own "affordability ranking" should definitely look beyond fuel burn per mile (or fuel burn per hour). If a hangar costs$200/mo and the plane is flown 50/year, that's \$48 per flight hour.
Reducing fixed costs ( sharing a hangar, trailering the plane home, being able to do inspections under a Repairman's Certificate, avoiding or reducing insurance costs, etc) can make a much bigger difference in the bottom line than trying for minimal fuel burn.
Absolutely correct that other fixed costs are the big issue compared to fuel burn. BUT the fixed costs are very related to airplane size and weight. smaller aircraft use less materials to build. they use smaller engines that often cost less to buy, operate and rebuild/service. Smaller aircraft are likely easier to fold up into a small space (all things being equal, which they never are...). Easier to load on a trailer or vehicle. Imagine if it was small enough to load on a pickup truck? efficiency is often related to these other costs too.....

A good example of inexpensive because it's small is the SkyPup from the list. uses various small engines that are inexpensive to purchase. materials can be less expensive because forces are smaller... and less materials used in any case. Wings come off for transport and storage.

Now, can a SkyPup be improved? probably..... and ideas to do that may be on other airplanes from the list-even the expensive ones. Even the ones that are not ultralights....

Small is also related to other important issues related to cost. Build time.....Build Space....

So there is my thought process starting point.

Last edited:

#### patrickrio

##### Well-Known Member
"Trade study" is simply a tool used to make decisions. If you pick up two different jars of salsa at the market, compare ingredients and price and then pick the most favorable, you have performed a trade study. Comparing aircraft specifications against requirements to determine the most favorable is also a "trade study"... It looked to me that your spreadsheet was the basis of your own trade study (because thats exactly what is done), so that explains my confusion.

See! you were on your way to a legitimate performance analysis and didnt even know it. You fit right in with the rest of us.
In some ways you are correct about my thinking... but a bit more nuanced. I am creating a list of airplanes that meet certain criteria so all of the different ways they met the criteria can be looked at easier. Maybe more like a grouping of a bunch of different ideas so they are easier to find...