I question the accuracy of several of your statements as I think that no matter how the hp is achieved, a certain amount of fuel/gas mixture is going to have to be burned for each hp and if the hp goes up the heat generated HAS to go up proportionately. You should consider that if you increase the stroke, that a greater qty of fuel air is being burned and that heat load will increase for the heads and valves etc as well.Applied,
I will consider doing a stroker in other models if appropriate. Gregory, that's a fair point, but the manner of increase matters. A higher compress and turbo will generate temperature increase rapidly. A longer stroke will only add heat to the half to three quarters inch cylinder section. While increasing higher rpm respiration likely will not increase temperature loads, except of course a friction componant. The same is true of boring the cylinder, except that therein you are more likely to ruin optimum rigidity, possibly effecting ring seal.
Interestingno thanks but this might interest you
It's a chunk of extra weight and money. It would lower fuel use. I'm going fixed pitch and will use whatever rpm that cruise takes.I am wondering what is thought of using a in flight variable pitch propeller
on the small engines say around 30hp+ like the 810cc Briggs & Stratton?
It is not likely warranted / desired for part 103 ultralights but for E/AB or E/AB Motor glider it may well be desirable as it can make useable power over a wider rpm band without going to even more weight of propeller speed reduction.
IVOPROP In-Flight Adjustable Ultralight Propeller The IVO is available @48"
dia. and will adjust down to 18" pitch. - MT also has a small electric
propeller but I am not sure it would be useful down to 30hp?
The weight would be around twice that of a similar size all wood propeller,
both would require the additional weight of a prop adapter.
It is a bit on the spendy side but may be warranted to maximize performance? I
mean if you intend to take-off at 35hp-ish around 3600rpm and cruise at 20hp
around 2800 rpm or something like that a fixed pitch is going to be extremely
inefficient at one end of the power curve or the other?
I have an adjustable Ivo that I bought just for my 810/Quickie project. Physically attaching it to the crank is going to be a significant project of it's own and probably forces the use of the PTO side with a bolt on 3rd bearing. If I could figure out a simple and elegantly way to add a 3rd bearing to the flywheel side I'll have to buy different blades.I think doubling the prop weight woud be asking a lot of these cankshafts and bearings in these small engines.
Unfortunately, one particular member keeps posting large amounts of nonsense. Most of small engineheads have him on ignore. But it only takes one new-ish person trying to call his BS to trash a conversation for a few days. Yeah, we could put the responders on ignore too, but I for one don't want to block the people with a clue. Despite many pleas, the mods have not reined him in.A comment on the concept of a private group on HBA.
If I understand the concept, a private group would be a thread that all can read, but only selected members can post to. If that is incorrect, please provide clarification.
Based on that understanding, my preference is that, with the exception of build logs, all HBA threads be available to be participated in by any registered member. When the inevitable thread drift occurs, the OP should refocus the conversation. Should the drift continue, the OP should report the problem to the moderators, who should address the offender.
When the inevitable disruptive post occurs, the OP should reply to the post, and point out the disruptive nature of the post. If others agree, they can support the OP’s position. If that does not correct the problem, then the OP should report the problem to the moderators, who should address the offender.
Moderators have been very lenient wrt allowing people to post ridiculous stuff as long as certain factors such as personal insults or links to pirated plans are avoided. I much prefer that approach to the creation of exclusive threads.