pilotdave

I was pretty surprised when I went from a PD-150 to a Sabre2 135. It has a much higher descent rate (but probably a better glide ratio except in tailwinds). Combined with the much softer (longer) openings, I noticed right away that I had a lot less time to play around with the Sabre2 and I had to start planning my pattern higher up. It sure is fun though, and going from an F-111 canopy to one with TONS of flare power makes it twice as fun. I'm curious... are you looking for low descent rates or high glide ratios? They aren't necessarily the same thing. Dave

Well, planes get designed to be most efficient in whatever flight regime they are expected to spend most of their time... at least in most cases. Jump planes spend the vast majority of their time in a cllimb, so that's what a pure jump plane should be designed for. Jump run and takeoff are of course also critical times for a jump plane. I don't think the tail design is terribly important as long as a skydiver can't hit it. High, asymmetric, whatever. Designing it for reliability and good flight characteristics goes without saying. T-tails are very well proven.... asymmetric tails are not. But any way you design it, it's gotta get certified the same way. Dave

The original was good. Dave

It's ok... I renamed the file to kill the old link anyway. You can feel free to link to the file's info page: http://www.skydivingmovies.com/ver2/pafiledb.php?action=file&id=2159. Dave

I've done spins in a tomahawk. Scariest thing I've ever done in a plane. The traumahawk has a lot of interesting behaviors in a stall or spin. When it stalls, it STALLS. Not like cessnas that kinda just get mushy. T-hawks have a very pronounced drop of the nose and almost always one wing drops too. The ailerons reverse in a stall, so trying to correct a right wing drop with left aileron will almost surely put you into a spin to the right. At the time, my instructor had only spun a t-hawk once before, so she told me she'd demonstrate but didn't want me touching the controls. She'd pull the nose nearly straight up...had to be 75 or 80 degrees nose up. Then it started like a normal stall... but as the nose crossed the horizon, one wing would drop and the nose would just keep going down. Suddenly we'd be pointed straight down, rolling. And the entire time the rudder made a clapping noise as it smacked against the tail from all the turbulent flow from the stalled wings. We only did 1/2 to 1 turn spins... she didn't want the spin to really stabilize. And every time we'd pull out, she'd have me look back at the tail and see if everything still looked like it was in place. Sounded like the rudder was gonna come flying off at any time. Man I miss those traumahawks. Dave

You've been registered on skydivingmovies.com for 1 year and 3 days and you haven't noticed I don't like direct links to files? C'mon now... it's in red, right below the download button. Links like that bypass registration. Then some guy posts the link on some whuffo forum. Then skydivingmovies.com gets innundated with hits, and downloads for us get even slower than they already are. This is why I require registration. Please, no direct links. BTW, this is exactly why one file on the site has about 3X as many downloads as any other, and why the server is extremely rate limited now. Ya crash a server at an ISP just once and they never forget. http://www.skydivingmovies.com/ver2/pafiledb.php?action=file&id=2159 Dave

Videos: 102 feet 88 feet 63 feet Dave

Who says? Doesn't say that in the FARs as far as I know. Dave

But an otter can fly with a canopy hanging from the stabilizer... A porter's stabilizer would be ripped off. That guy (and the pilot, etc) got LUCKY. Both videos: http://www.skydivingmovies.com/ver2/pafiledb.php?action=search&search=do&string=wffc_2004_canopy_accident.mpg%20overthetop&searchtype=anywords&click=1 Dave

Obviously it's only an approximation, using 0.7 as an average drag coefficient of a pilot chute. A quick google search shows that 0.7 is a typical drag ratio for a flat circular parachute. Pilot chutes range from 0.4 to 1.0. That makes 0.7 a pretty good average, if you trust the internet. You can redo all the math at 0.4 if you want to be more conservative. Dave

Holy shit, he was awesome....saw him live once. Did his entire act with his eyes closed....very odd but hilarious. Dave

My aerospace engineering opinion agrees with you completely. High tails have advantages and disadvantages. Structurally, it's usually a disadvantage because the vertical tail must be made stronger to support it. But since it sits outside the wake of the fuselage/wings in cruise, it can often be made smaller, saving weight. At the same time, since it's outside of the downwash from the wing (as opposed to the wing/stab arrangement cessna singles), it has to generate more down force on it's own to counter the negative (nose down) pitching moment of the wing. In a stall, a high horizontal stabilizer may be sitting right in the turbulent wake from the wing/fuselage, reducing it's effectiveness to get the plane out of the stall. Because of the structural issues and the stall issue, you don't often see high tails on aerobatic planes. You mostly see them on airliners, etc, which can take better advantage of the weight savings of a smaller stabilizer without needing a huge beefup of the tail since they won't be pulling a lot of Gs, and they're also very unlikely to ever be stalled. High tails also require more complex routing of control cables, and like you said are harder to inspect/maintain. A jump plane is more likely to be stalled, but it's all a tradeoff. If someone was designing a plane from scratch to be used for jumping, they surely would keep the tail high enough that it couldn't be hit. A twin otter uses a cruciform tail....halfway in between a t-tail and a low tail. It's a tradeoff. But the position of the tail is just one of many factors that come into an aircraft design. On a jump plane, a high tail is sort of a must. So you design the rest of the plane to compensate as necessary. Dave

Well if you're paying to have the service done anyway, might as well keep it for another 4 years at least. Have you changed your mind about AADs for some reason, or did you never feel it was necessary? What makes you think you won't ever need yours when so many others have needed theirs? Course the vast majority of cypres fires occur during/right after pulling the main. That's why so many people think AADs INCREASE your overall risk. It's been proven over and over and over again that when skydivers go low, they go for their main. Personally I'd rather take my chances with 2 out rather than nothing out. Dave

.mp4 files will play in quicktime. Dave

Yeah...my DZ teaches to throw the cutaway handle, but hold the reserve handle since it's a lot more likely to cause an injury or damage. Throwing the cutaway handle get's it out of the way and get's the jumper's hands clear to pull the reserve. Dave

If they just block the URL "skydivingmovies.com" and not the IP address of the site, you might get in with http://sdm.crocker.com. Doubt it though. Dave

If you said it in french, probably. Many of those technical for airplane parts are in french for some reason. I never figured out how that happened since they first showed up on american designs. ie canard, aileron, etc. Dave

I didn't do a full stall until I took a canopy course with Scott Miller. It's just one more way to learn about flying your canopy. Taking it right to a limit, but under safe, controlled conditions. If I had ever done a full stall by mistake before taking the course, it woulda scared the crap out of me. But when Scott shows a video of what it's going to look like, and then you go up there and see the exact same thing (the canopy folding right in half, like an F-14 sweeping it's wings), it just builds confidence and you'll know the warning signs so you never get into that situation by mistake. It's fun too! Dave

Well, that's very true that anything can fail, but we have no choice but to rely on some of our equipment. Hook is skipping the stuff we have no backup for, like the harness and reserve. I am a huge believer, although its a very unpopular idea among the old timers, that the human is the weak link in the chain. At work, in the world of System Safety Engineering, relying on humans to do the right thing is absolutely the least desirable type of hazard mitigation. All those old (and young) guys that say their left hand is their AAD don't seem to understand that. But just for the sake of disagreeing with you, AADs are different from the rest of our equipment. They're like airbags. They try to save your ass after something has gone wrong. Even if they were proven to work 100% of the time, I'd still agree with hook that we should avoid needing the AAD (in particular) by only jumping within our skill/currency level. Even when the AAD works, you might still already be dead. I think that sets it apart from reliance on an audible or a reserve or a harness or whatever. Dave

Just because this site is full of conspiracy theorists doesn't mean you need to apologize. In my opinion, the only thing you do owe the world an apology for is being a texan. I gotta go... Dave

I just got my issue. I'm wondering if the pouch maybe looked like it was full of drug paraphanelia? The CO2 cartridge looks like a nitrous container, etc. Was that the objection? Dave

Just a quick lesson in video compression: file size is meaningless! Check out the attached screenshots. First one is the original 61 meg video. Second one is the 3.6 meg video. Open em side by side! Dave

Ok, uploaded. 3.6 megs and deinterlaced for a smoother picture. Same link. Dave

Doing it now... looks like I can get it down to just a few megs without too much quality loss. Dave

Thought some of you would enjoy this 8 minute clip from late 80's TV about BASE jumping: http://www.skydivingmovies.com/ver2/pafiledb.php?action=file&id=1452 Any familiar faces? Dave