Question about YORS Lil Hustler fin patterns.

[rraeford]

I just downloaded the pdf files for the Lil’ Hustler form YORS and I'm confused about the size of the fins. There’s a note on the fin scan that reads “ Root Chord = 2.3".” Okay. easy enough. I enlarged the printout so that the root chords measured 2.3".

Also included in the pdf is a scan of the kit parts done on a flat bed scanner. This scan shows two fins, a nose cone and transition as well as a 6" ruler. I printed this scan out and made certain the 6" ruler measured 6". Then I just happened to lay this printout on top of my correctly upsized fin pattern (at 2.3" per the pattern sheet) and noticed the fins were different sizes – a lot different.

I measured the parts scan root chord and it appears more like 3". It's difficult to tell exactly because the fins in the scan are rounded a bit and appear to have been broken off of an old model but that's a big discrepancy.

Question: which is right? Did I do something wrong? Has this been discussed before?

Any help would be greatly appreciated.

Romie

[CPMcGraw]

I just downloaded the pdf files for the Lil’ Hustler form YORS and I'm confused about the size of the fins. There’s a note on the fin scan that reads “ Root Chord = 2.3".” Okay. easy enough. I enlarged the printout so that the root chords measured 2.3".

That measurement is a bit off...

I'm looking at a "stitched together" image with the leading edge extension in its proper place, taken from the scan on YORP. These are supposed to be "full size" images already. Taken together, the full root edge comes to 3 7/16". The span of the fin is 3 11/16"

Also included in the pdf is a scan of the kit parts done on a flat bed scanner. This scan shows two fins, a nose cone and transition as well as a 6" ruler. I printed this scan out and made certain the 6" ruler measured 6". Then I just happened to lay this printout on top of my correctly upsized fin pattern (at 2.3" per the pattern sheet) and noticed the fins were different sizes – a lot different.

The Lil' Hustler fin is a two-piece fin. The scans look more like those of the Scorpion (one piece with no forward strake).

I measured the parts scan root chord and it appears more like 3". It's difficult to tell exactly because the fins in the scan are rounded a bit and appear to have been broken off of an old model but that's a big discrepancy.

Question: which is right? Did I do something wrong? Has this been discussed before?

Any help would be greatly appreciated.

Romie

The sheet of balsa those fins come from is 4" wide, so you should be able to overlay that pattern directly to the balsa sheet.

For reference, that pattern sheet was scanned at 100 DPI, and measures 1159 px high, and 752 px wide.

[rraeford]

I printed the scans you posted and the root chord of the fin (without the strake) is indeed 2.3".

So...I guess the scan of the parts is wrong. Perhaps those fins are from another model? Possibly a Hustler? Who knows?

These seem to be what I need. Many thanks.

Romie

[CPMcGraw]

I printed the scans you posted and the root chord of the fin (without the strake) is indeed 2.3".

So...I guess the scan of the parts is wrong. Perhaps those fins are from another model? Possibly a Hustler? Who knows?

These seem to be what I need. Many thanks.

Romie

Then maybe I'm the one who's off-kilter, just a bit. I just went back and measured the root edge of the main fin piece and came up with 230 px, which is exactly 2.3". That figure is correct, and not my previous comment. Sorry. My head has been congested with...stuff...for several days, so my thinking ability should be considered suspect right now...:o

[CPMcGraw]

Romie,

What tube lengths are you working with? The lengths in the two text files are most assuredly wrong, if the length in the catalog (29") is itself correct...

Here's what I've come up with so far:

The nose cone is 6.7" long. This matches the SEMROC BC-17567...

The transition is 2.1" between the shoulders. This matches the SEMROC BR-125-175...

The distance between the rear edge of the main body tube and the tip of the fin TE is ~0.5"...

So, 29.0" - 6.7" - 2.1" - 0.5" = 19.7" total length for the main body tube and the payload body tube together. The text files show 16" for the main tube and 6" for the payload tube, or 22". That's 2.3" beyond the catalog length...

What measurements are you working with?

[rraeford]

Well...until I read your post I was working with the measurements in the text document. So, now I'll be checking out other sources.

Dang. There's that 2.3" thing again.

Romie

[stefanj]

I'm following this thread carefully. I have the parts for a Lil' Hustler. It is the only "MiniMax Era" models I haven't built.


I'm glad that the fin size issue has been resolved!

Has anyone carefully examined the scanned in kit directions? The "Enerjet Era" plans have some clues. The diagram showing launch lug placement suggests a main body tube that is at least 19" long:

2 1/2" from front of tube to front of fore launch lug.

Launch lug is at least 2" long. (There's also the standoff.)

10" between launch lugs.

Another 2" for aft launch lug.

Rear of aft launch lug is ahead of leading edge of fins. The fins, with front gusset thing, is at least 2 1/2"

I'm guessing that it is a 20" or 22" tube.

[CPMcGraw]

Rear of aft launch lug is ahead of leading edge of fins. The fins, with front gusset thing, is at least 2 1/2"

I'm guessing that it is a 20" or 22" tube.

The full root edge length, including the LE strake, is 3 7/16" long. The root edge of just the main fin is 2.3".

So, if we take 20", plus 0.5" for the fin TE tip, plus 2.1" for the transition, plus 6.7" for the nose cone, and 6" for the payload tube, the length of this model is now 35.3". BIG DIFFERENCE from a catalog length of 29"...

If we only use a 4" payload, it's still 33.3"...

[Ltvscout]

If people are unsure of the dimensions listed (tube lengths are also in the PDF), they should probably contact the people listed as supplying the scans. That would be Paul Graf, Sean Lannan and Larry Rice.

[rraeford]

Craig wrote:

...So, if we take 20", plus 0.5" for the fin TE tip, plus 2.1" for the transition, plus 6.7" for the nose cone, and 6" for the payload tube, the length of this model is now 35.3". BIG DIFFERENCE from a catalog length of 29"...

Yeah, this gets curiouser and curiouser. The Centuri catalogs of the day have more than one or two errors when compared to the final production kits. For example: the Hustler kit is listed as 37" long and yet it must have been at least 39.6" long based on every piece of info I've ever seen. Semroc has their Hustler clone at 39.7". So which is right? My money is on Semroc.

I usually err on the side of measured kit dimensions. In the absence of this, I look to standard tube lengths (although I'm not sure why we should trust those!). For the Minimax kits those tube lengths were 22", 30" and 8". Again, this is according to the 1971 Centuri catalog. Trouble is, if you look at the photos of the Lil' Hustler (which are heavily airbrushed as all catalog images were in those days) then there's no way this model had an 8" payload section. In other words, I agree with the 20" body and 6" payload measurements. So, unless someone knows better or has an actual kit they've measured, I'll have a 35.3" long clone.

BTW, does anyone know whether or not the Aerodart of 1971 used the same fin patterns as the Lil' Hustler or the Hustler? Becuase they sure look the same.

Romie

[rraeford]

BTW, I've emailed Paul Graf about the scans.

Romie

[Ltvscout]

BTW, I've emailed Paul Graf about the scans.

Romie
I "think" that Paul only supplied the scans of the plans. I could be wrong. I believe the template scan, parts scan and listed dimensions came from Sean Lannan and Larry Rice. Sean is a frequent visitor here. You could PM him at his handle of SEL. Larry you'd have to contact via email at larryr33323@yahoo.com.

[SEL]

I "think" that Paul only supplied the scans of the plans. I could be wrong. I believe the template scan, parts scan and listed dimensions came from Sean Lannan and Larry Rice. Sean is a frequent visitor here. You could PM him at his handle of SEL. Larry you'd have to contact via email at larryr33323@yahoo.com.

Time for me to chime in here. The copy of the fins and templates that I provided were scanned from a (at least!) second generation photocopy that I obtained from R. Michael Jungclas way-back-when. So, keeping that in mind, along with the fact that that I may have been a little vague about what I was refering to as the "root chord", here's what I have: By "root chord " I meant the part of the fin that is actually glued to the airframe, which measures 2.3". It does not include the part of the fin that flares out at the trailing edge - this adds another ~.5 ". The little thingy that attaches to the airframe at the leading edge measures ot to just under 1.3". This gives us a total length of 4.1". The "tip chord" measures out to ~1.35". Like I said, it's not a great copy, but I can just make out the outline of the printed balsa sheet, and that measures out to close enough to 4" that I'm calling it 4". I'm not sure who supplied the parts scans, but he should be able to help out with th BT lengths.

Sean

[stefanj]

Not all kits in the "Large Scale Rocketry" line had standard-length (e.g., 8" or 22") tubes.

The Explorer had a 20" tube.

The Lil' Hustler almost certainly has a 6" payload tube; clues in the older plan set suggest this.

The remaining question: How long is the main body tube?

[Ltvscout]

The remaining question: How long is the main body tube?
Did you guys pull up the latest PDF from the site for those plans? All the tube lengths are listed on the last page.

[CPMcGraw]

Did you guys pull up the latest PDF from the site for those plans? All the tube lengths are listed on the last page.

We must all be suffering from head-crud right now...

I just pulled the PDF from YORP...

15" on the LT-125 (main body tube), and 5 1/2" on the LT-175 (payload body tube). I'd say those come under the heading of "non-standard lengths"...

15.0" + 5.5" + 2.1" + 6.7" + 0.5" = 29.8"...

That's closer to the ballpark than 33" or 35". Thanks for the reminder, Scott...

And we all know those plan sheets were sometimes off a bit with dimensions and relative parts positions...

[rraeford]

Scott wrote:

Did you guys pull up the latest PDF from the site for those plans? All the tube lengths are listed on the last page.


Yes. I did see this but with the other problems I found I thought I might try to confirm the tube lengths. I was hoping whoever wrote those sizes down would chime in here and say where they came from.

It doesn't really matter. For a clone of a model that very few people have ever seen, much less taken measurements of, I think I can build with confidence. I just hate finding out later that I was off by a smidge I could have avoided if I'd just asked the question.

Thanks to all who responded.

Romie

[stefanj]

I am pretty sure that the payload section tube is 6" long, not 5 1/2".

The plans (early set) says that the compartment can fit payloads up to 4 1/4" long.

The shoulders of the nose cone and reducer are 5/8" and 1 1/8" respectively.

6" - 5/8" - 1 1/8" = 4 1/4".

My earlier pictorial guesstimate of the main body tube length were based on a 2" launch lug length. Now that I printed out the plans, I see that the Lil' Hustler used 1" launch lugs. I think a 16" or 18" main tube is more reasonable.

I started marking out fins and filling the balsa parts today. I'm using 1/8" basswood and through-the-wall mounting for the fins.

I hope to duplicate the roll bar shown in the 1971 catalog. I doubt it was ever an actual decal, but I think it looks neat.