APenNameAndThatA

There is a guy on here who has carefully tested props and reckons that they all perform about the same. Truth — I have no clue.

The above only takes into account the blade efficiency. So it’s basically wrong. What you could do is compare the revs at WOT on cruise and takeoff. If the WOT RPM at takeoff is higher than at WOT RPM at cruise, you will be able to calculate the engine power difference from charts that show power at full throttle at different density altitudes and different RPM’s. From the difference in power, you will be able to calculate (speculate about) how much extra power you will have from a CS prop. Are you allowed to cruise at WOT in a 3300? (can in a Rotax). Is max RPM for takeoff same as max RPM in cruise (higher in a Rotax, which is a reason for CS props in a Rotax.) Another factor is that if you move your C of G forward with the 8 kg on the nose, you will reduce your efficiency because your elevators will need to produce more downforce. I don’t know if significant. Stall speed higher, too, IIRC. Don’t know if significant. I suppose your Cof G envelope will tell you if it is too far forward.

I think that if a CS prop actually gave a 33% shorter ground roll AND a 20% improvement in cruise then you would get much less argument from people. I bet the performance improvement would be nowhere near that good. I think the disconnect in the convo is that no one believes those figures. To get a 20% improvement in cruise, you need to effectively have 1.73 times more power. I the efficiency of your standard prop is 0.6, then that is not possible. IIRC, the average prop has an efficiency of 0.8. (By efficency, I mean converting engine power to prop power/work. (1.2 cubed = 1.73) (As for the mighty Foxbat: revs just below yellow on takeoff and just below yellow full throttle at 8000 ft cruise!)

It is *generally* accepted that the mass of 1 L of water is 1 kg. Everything else is pretty light. I can’t see myself carrying a jack but Im not saying that it is wrong.

The easiest thing to do would be to donit the old way and the new way, and gradually change over. I use Ozrunways. It would probably be best ti use to app your friends use. Also, consider the size iPad you want. I use an iPad mini and it stays up out of the sun, over the passenger’s head, on the right wingroot. Most I see are much bigger. iPads are worth using because they speed up incorporating winds and weather into your plan immediately before you take off. You input the plan in advance, and then incorporate the winds and etc just before you take off.

(But you still need an iPad that gas GPS, which means it needs to be capable of data downloads, IIRC)

You might, and might not, want to check with your insurer.

Post of the week. I didn’t know about the powerlines beneath the southern circuit at Archerfield! I suggest you start a new thread to let everyone know about the app.

How low is too low?

What do you all think of x canisters of tyre inflation goo vs carrying spare tubes and etc?

What is a neck?

Like someone else said, email rather than phone, so you have it in writing, IMHO.

Survival gear and repair gear are two different things, of course. I am very happy for both things to be discussed in the same thread. The only repair-ish things I carry are Leatherman multitool, small shifting spanner, type pressure gauge, small right-angle extension so I can get to the valve stem when inflating, tyre inflation air and puncture repair goo in an aerosol can, 2 m tape measure, tie down ropes, ground anchors, drill bit to get the ground anchors in, ratchet to rotate ground anchors, 1 L oil, duct tape (for fabric control surfaces), some weird tape that sticks to itself (very light), cord, fuses, and microfibre cloth for the windscreen. Disclaimer: I have only 185 hrs and would probably wreck a tube if I tried to repair it.

I thought what you did was reasonable.

That airline name did not age well.

You posted the question because you did not know the answer? Really? Is that how come you argued with the replies? 😆

I thought drag was proportional to velocity squared. And power required was proportional to velocity cubed. And the difference was because you need more power to go faster for a given amount of drag. P.S. I am amazed by how much you and others on here know.

I remember reading about someone who flew through a valley and then saw later that there was a power line strung across it. I have been tempted to fly low over hills avoiding headwinds - not clever of me.

I notice that OME did not acknowledge this answer. The first time I remember OME posting a question on the forum, he was trying to say that if an aircraft was trimmed in cruise and lost some power, it would slow down. I pointed out that if a trimmed aircraft loses some power, it will descend rather than slow down. Crickets. To be fair, he did acknowledge someone was right when he said that the lift equation was based on true airspeed rather than IAS and he was corrected. I didn't even think of those equations. I just thought that the issue fell outside the equations because the aircraft moved with the air mass.

OME, you are not in a position to teach other people in the forum because the people who you try and teach understand your questions better than you do. OME, you are not using Socratic questioning. You asked one question a the start, and then were mostly making wrong statements. Socratic questioning involves leading students, step by step, question by question until they learn something they already knew, as it were. I can just imagine Socrates asking his students questions where he's not as smart as them, and becoming more and more frustrated when they don't answer the questions the way he wants them to, and telling them how upset they make him. I just saw OME write "gone" on the forum. Maybe he's going to disappear for another 12 months. While he's away, maybe he'll work out that the mass of one litre of water is not 100 g. So, then Socrates would storm off out of the forum.

This is an aviation forum, so people are obliged to callout incorrect ideas. I never managed to convince you that the mass of one litre of water was not 100 grams so here I was not going to go beyond merely pointing out to you that you are wrong. Okay, I’ll give the mass thing one more shot. The F in the formula F=ma is measured in newtons, not kg. That is how come, when it comes to gravity, it is 10 times bigger than mass. IIRC, you posted a picture of a spring scale. On one side the scale showed the force in newtons and on the other side the scale showed the force in kg. Some things do indeed never change, like you posing questions to teach people things and then getting upset when people don’t answer the way you want. Sometimes I wonder if your posts are an elaborate joke, but then I remember that you have gotten me booted off the forum for disagreeing with you.

You didn’t ask the question to improve your own knowlege…

Y all have to admit that the idea of gliding into the wind to maximise your glide distance is worth some LOL’s. 👍😆👍

You most often want to glide to the best place to land. BUT if you want to maximise the distance you can glide, you will turn so you have a tail wind… and you will stay aloft for the same amount of time. 😆

Bit off topic. I find submitting a sartime with the naips app quicker than submitting a flight plan with ozrunways even if I have already done the flightplan with ozrunways for fuel and etc. Im a noob. To not answer your question, Id use both for a time and see. I assume you have adsb on the garmin? Nice profile plane, btw.