LOC I-Roc Question

[Rob Campbell]

I just bought a LOC I-Roc. It doesn't come with instructions. I am confused on the orientation of the fins. They appear symmetrical, but they aren't. If I attach thr fins with the laser burned IROC name reading down there is slightly more sweep on the leading edge. If IROC reads up, there is more sweep on the trailing edge.

Please advise.

 

[Aeva]

https://cdn.shopify.com/s/files/1/0568/7489/3503/files/PK-76-IROC-Instructions.pdf?v=1623744289

their instructions are listed on the webpage

Also, can you post a pic of these fins? They look symmetrical on the webpage... but it sounds like from your description that they're airfoiled. IIRC the blunter end would go forward, and the more tapered/longer sweep is the aft end. E: You can check the sim for the orientation:



https://cdn.shopify.com/s/files/1/0568/7489/3503/files/IROC.zip?v=1623744228

The leading edge has less taper, and the aft edge has steeper taper. More simply: there should be no overhang between the aft of the rocket and the placement of the aft end of the fin.

 

[Art Upton]

I might be blind, but I don't see anything talking about what the OP is asking for ?

My I-Roc back in the Ron days, and after it's demise the replacement in the Barry days; did not have any top or bottom, they were the same on both sides and had no markings at all. So I am of no help...

Edit: generally with fins that are swept the sweep is on the leading edge, unless your wanting to make a rocket that looks different like a Goblin with the fins pointing up instead of down and call it a Nilbog.

 

[AlexBruccoleri]

I was not sure on mine and I just made sure to be consistent. I recommend asking LOC directly. They are very helpful!

 

[crossfire]

https://cdn.shopify.com/s/files/1/0568/7489/3503/files/PK-76-IROC-Instructions.pdf?v=1623744289

their instructions are listed on the webpage

Also, can you post a pic of these fins? They look symmetrical on the webpage... but it sounds like from your description that they're airfoiled. IIRC the blunter end would go forward, and the more tapered/longer sweep is the aft end. E: You can check the sim for the orientation:

View attachment 640241

https://cdn.shopify.com/s/files/1/0568/7489/3503/files/IROC.zip?v=1623744228

The leading edge has less taper, and the aft edge has steeper taper. More simply: there should be no overhang between the aft of the rocket and the placement of the aft end of the fin.

I just bought a LOC I-Roc. It doesn't come with instructions. I am confused on the orientation of the fins. They appear symmetrical, but they aren't. If I attach thr fins with the laser burned IROC name reading down there is slightly more sweep on the leading edge. If IROC reads up, there is more sweep on the trailing edge.

Please advise.

Just call LOC and ask them. They are really good help.

 

[Titan II]

https://www.rocketreviews.com/unknown-pk-76-iroc.html

 

[-Slick-Ice]

The I-ROC I bought myself for Christmas last year the fins were completely symmetrical. The ORK file was very wrong.

 

[Titan II]

https://locprecision.com/products/i-roc-fin-set-qty-4-1-4-baltic-birch

 

[Rob Campbell]

I emailed LOC. I expect a response before I'm ready to epoxy the fins in place.

 

[-Slick-Ice]

Ignore the mud I still haven't cleaned off.

 

[-Slick-Ice]

I also don't think any other 5.5" kit came with a 38mm motor mount. Make sure the through-the-wall tabs are the correct length. I would agree that nothing should be passed the end of the body tube.

 

[John Kemker]

I also don't think any other 5.5" kit came with a 38mm motor mount. Make sure the through-the-wall tabs are the correct length. I would agree that nothing should be passed the end of the body tube.

Warlok

 

[RocketRev]

I also don't think any other 5.5" kit came with a 38mm motor mount. Make sure the through-the-wall tabs are the correct length. I would agree that nothing should be passed the end of the body tube.

Mini-Mag also comes with a 38mm mmt

 

[Rob Campbell]

I also don't think any other 5.5" kit came with a 38mm motor mount. Make sure the through-the-wall tabs are the correct length. I would agree that nothing should be passed the end of the body tube.

The discontinued Big Cletus

 

[Rob Campbell]

I received a reply from LOC confirming the greater sweep goes to the trailing edge of the fin. Thanks to all who replied. I appreciate the assistance.

 

[Tim51]

I received a reply from LOC confirming the greater sweep goes to the trailing edge of the fin. Thanks to all who replied. I appreciate the assistance.

I don't know which came first, but I'm guessing the I-Roc's a kind of fatter, smaller field variant of the EZI-65, built for high thrust 38s rather than longer burn 54s.

 

[Art Upton]

I don't know which came first, but I'm guessing the I-Roc's a kind of fatter, smaller field variant of the EZI-65, built for high thrust 38s rather than longer burn 54s.

The EX-I 65 was out long before the I-Roc. I was at Danville Dare when Deb and Ron [Original owners of LOC] showed off the new I-Roc [1990?] and I won the Raffle prize and got the first one bagged for sale. At that time the nose cone was 'slightly' transparent on that first run.

Almost 2 decades later the new owner Barry was LCO at the Cleveland 'Skybusters' club launch and my I-Roc was going up. He said it was the longest flying I-Roc out there. The pro38 delay train snuffed out and never lit the ejection charge. That nose cone and most of the body tube were ruined in the semi-core sample.

Out of kindness, Barry gave me a brand new I-Roc kit. I have flown it many times and still have it upstairs here in the house.

 

[Tim51]

The EX-I 65 was out long before the I-Roc. I was at Danville Dare when Deb and Ron [Original owners of LOC] showed off the new I-Roc [1990?] and I won the Raffle prize and got the first one bagged for sale. At that time the nose cone was 'slightly' transparent on that first run.

Almost 2 decades later the new owner Barry was LCO at the Cleveland 'Skybusters' club launch and my I-Roc was going up. He said it was the longest flying I-Roc out there. The pro38 delay train snuffed out and never lit the ejection charge. That nose cone and most of the body tube were ruined in the semi-core sample.

Out of kindness, Barry gave me a brand new I-Roc kit. I have flown it many times and still have it upstairs here in the house.

I thought the EZI preceded the I-Roc but wasn't sure of the history - thanks for confirming, and for the background story. I like the look of it but I have yet to see one this side of the pond.