So you want to fly? What, When, Where, Why, How

cralkhi wrote:Even so, airplanes are one of the applications where liquid fuel and internal combustion make the most sense.

"Liquid Fuel" =/= "Fossil Fuel"

If ICEs are developed for aviation, they a) Don't need to be reciprocating engines, and b) can be turbo-prop gas turbine engines that will run on any flammable liquid.

Still, we've argued ICEs to death, without addressing where aircraft are going to land and takeoff. Are land-based airplanes going to dominate; are they going to need square miles of flat, open space for runways?

Or is Safehold aviation going to be water-based with designs like the China Clipper, Martin Mars, or H4 "Hercules" going to dominate aviation?

Weird Harold wrote:

cralkhi wrote:Even so, airplanes are one of the applications where liquid fuel and internal combustion make the most sense.

"Liquid Fuel" =/= "Fossil Fuel"

If ICEs are developed for aviation, they a) Don't need to be reciprocating engines, and b) can be turbo-prop gas turbine engines that will run on any flammable liquid.

Still, we've argued ICEs to death, without addressing where aircraft are going to land and takeoff. Are land-based airplanes going to dominate; are they going to need square miles of flat, open space for runways?

Or is Safehold aviation going to be water-based with designs like the China Clipper, Martin Mars, or H4 "Hercules" going to dominate aviation?

If you are worried about pollution, sea planes are not a good way to go. IIRC, the China Clippers used approximately 30% of their fuel load to just take off. That's a lot of pollution for very little result.

fallsfromtrees wrote:If you are worried about pollution, sea planes are not a good way to go. IIRC, the China Clippers used approximately 30% of their fuel load to just take off. That's a lot of pollution for very little result.

The China Clippers and other flying boats of that era were seriously under powered and didn't have hydrofoils or any of the later innovations that make taking off more efficient. Simply replacing the reciprocating engines with turbo-props would do away with a lot of the problem.

I'm not all that worried about the pollution from a few hundred or even a few thousand flying boats; it is the many billions of automobiles (including trucks and motorcycles) that make any change from fossil fuels and ICEs so unfeasible.

If the Empire of Charis needs an airplane soon, the obvious power plant is a pulse jet.

Pulse jets -- at least basic pulse jets -- are not a very good power plant in terms of fuel efficiency or noise, but it's simple and light and it presents a great opportunity to use Owl to cheat. Plus it has industrial applications as a technology and doesn't require an electrical system of any kind.

It also has to be a better plan than trying to make rotary engines reliable or trying to build an aircraft diesel when you're just getting the hang of steam.

Because pulse jets don't do very well for high specific thrust, steam catapult launching might be considered.

Graydon wrote:If the Empire of Charis needs an airplane soon, the obvious power plant is a pulse jet.

...

Because pulse jets don't do very well for high specific thrust, steam catapult launching might be considered.

What kind of aircraft would you mount your pulse jet in and/or where would you mount your steam catapult?

Where are you going?

What are you going to do?

Where are you going to land?

Graydon wrote:If the Empire of Charis needs an airplane soon, the obvious power plant is a pulse jet.

Pulse jets -- at least basic pulse jets -- are not a very good power plant in terms of fuel efficiency or noise, but it's simple and light and it presents a great opportunity to use Owl to cheat. Plus it has industrial applications as a technology and doesn't require an electrical system of any kind.

It also has to be a better plan than trying to make rotary engines reliable or trying to build an aircraft diesel when you're just getting the hang of steam.

Because pulse jets don't do very well for high specific thrust, steam catapult launching might be considered.

I very much hope that you don't mean a Schmidt type pulse jet ala V-1. The Luftwaffe had several projects to use Schmidts on manned aircraft and had several unsolvable problems with them. Acoustic stress on the crew, acoustic stress on the airframe and physical stress on the airframe caused by the continuous positive and neutral G forces.

One problem which hasn't been addressed in this topic in re flying machines on Safehold is the fact that aluminum will not be available for either airframes or engines. Aluminum requires the use of electricity to obtain the metal from the ore, and electricity is definitely a no-no!
Without aluminum, the weight of any projected flying machine is going to be probably close to twice what it could have been otherwise - a major obstacle.
Philip Stanley

Philip Stanley wrote:One problem which hasn't been addressed in this topic in re flying machines on Safehold is the fact that aluminum will not be available for either airframes or engines. Aluminum requires the use of electricity to obtain the metal from the ore, and electricity is definitely a no-no!
Without aluminum, the weight of any projected flying machine is going to be probably close to twice what it could have been otherwise - a major obstacle.
Philip Stanley

There were any number of aircraft built without aluminum - virtually all WWI aircraft were built from wood, so no aluminum is not a prerequisite for aircraft.

fallsfromtrees wrote:

Philip Stanley wrote:One problem which hasn't been addressed in this topic in re flying machines on Safehold is the fact that aluminum will not be available for either airframes or engines. Aluminum requires the use of electricity to obtain the metal from the ore, and electricity is definitely a no-no!
Without aluminum, the weight of any projected flying machine is going to be probably close to twice what it could have been otherwise - a major obstacle.
Philip Stanley

There were any number of aircraft built without aluminum - virtually all WWI aircraft were built from wood, so no aluminum is not a prerequisite for aircraft.

Well, to build them larger than say the planes used in the 1920-early 30s would be difficult because planes started to use aluminum as the metal for the skin and aircraft frames. Wood only works to a certain point, after which you need metal. Hence the need to find a way to neutralize the OBS.

doug941 wrote:

Graydon wrote:If the Empire of Charis needs an airplane soon, the obvious power plant is a pulse jet.

I very much hope that you don't mean a Schmidt type pulse jet ala V-1. The Luftwaffe had several projects to use Schmidts on manned aircraft and had several unsolvable problems with them. Acoustic stress on the crew, acoustic stress on the airframe and physical stress on the airframe caused by the continuous positive and neutral G forces.

Nope. Those have serious problems with valve lifetime, too.

This is where having Owl handy to cheat comes in; you can use a valveless pulse jet, which is not much more than a very specific shape of pipe. No moving parts, very low maintenance. Those that have flown are still loud and get hot but they're not rattly. Owl gives you the acoustic -- the things depend on acoustic standing waves and precisely calculated resonator pipes -- design and possibly the advanced forms where you feed one into the other for better compression and thrust.